WO2019244351A1 - Liquid crystal display device and method for producing same - Google Patents

Liquid crystal display device and method for producing same Download PDF

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Publication number
WO2019244351A1
WO2019244351A1 PCT/JP2018/023850 JP2018023850W WO2019244351A1 WO 2019244351 A1 WO2019244351 A1 WO 2019244351A1 JP 2018023850 W JP2018023850 W JP 2018023850W WO 2019244351 A1 WO2019244351 A1 WO 2019244351A1
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WIPO (PCT)
Prior art keywords
layer
liquid crystal
crystal display
phosphor
display device
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Application number
PCT/JP2018/023850
Other languages
French (fr)
Japanese (ja)
Inventor
岩本　健一
真由美 堀
和彦 根来
Original Assignee
堺ディスプレイプロダクト株式会社
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Application filed by 堺ディスプレイプロダクト株式会社 filed Critical 堺ディスプレイプロダクト株式会社
Priority to US17/254,243 priority Critical patent/US11561433B2/en
Priority to PCT/JP2018/023850 priority patent/WO2019244351A1/en
Publication of WO2019244351A1 publication Critical patent/WO2019244351A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133605—Direct backlight including specially adapted reflectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/075—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00
    • H01L25/0753—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00 the devices being arranged next to each other
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133504—Diffusing, scattering, diffracting elements
    • G02F1/133507—Films for enhancing the luminance
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G02F1/133607—Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133614—Illuminating devices using photoluminescence, e.g. phosphors illuminated by UV or blue light
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements
    • H01L33/501—Wavelength conversion elements characterised by the materials, e.g. binder
    • H01L33/502—Wavelength conversion materials
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2202/00—Materials and properties
    • G02F2202/28—Adhesive materials or arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
    • H01L2933/0091—Scattering means in or on the semiconductor body or semiconductor body package
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/44—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/58—Optical field-shaping elements
    • H01L33/60—Reflective elements

Definitions

  • the present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly, to a liquid crystal display device having an LED backlight and a method for manufacturing the same.
  • a backlight device having a plurality of LEDs.
  • the plurality of LEDs are divided into, for example, a plurality of regions, and only the LEDs in the region where illumination light is required are turned on, or the brightness is adjusted to the required luminance for each region.
  • Such a driving method of the backlight is called divided driving, partial driving, area driving, or local dimming.
  • the division driving method is employed, the contrast ratio of the brightness between the bright part and the dark part of the liquid crystal display device can be improved.
  • HDR High Dynamic Range
  • Patent Literatures 1 and 2 a remote phosphor method is adopted as a liquid crystal display device capable of complying with the UHD @ Premium standard (color reproduction BT2020 standard 90% or more, HDR10 standard), and A liquid crystal display device that suppresses color unevenness using a dichroic filter has been studied.
  • the object of the present invention is to improve the performance of a liquid crystal display device including a backlight device of a remote phosphor type, including thinning, and / or to improve the mass productivity.
  • a liquid crystal display device is a liquid crystal display device including a liquid crystal display panel and a backlight device that emits light toward the back of the liquid crystal display panel, wherein the backlight device is An LED substrate having a plurality of LED chips arranged on a surface thereof so as to emit excitation light toward the rear surface of the liquid crystal display panel; a phosphor layer containing a phosphor that receives the excitation light and emits fluorescence; A wavelength selective reflection layer disposed between the phosphor layer and the LED substrate, wherein the transmittance of the excitation light is higher than the transmittance of the fluorescence; and an optical element disposed on the liquid crystal display panel side of the phosphor layer.
  • the optical layer laminate, the phosphor layer, and the wavelength selective reflection layer are integrally formed on the back surface of the liquid crystal display panel via a plurality of adhesive layers including a first adhesive layer.
  • the first adhesive layer is formed between the optical layer laminate and the phosphor layer, and the first adhesive layer has a plurality of discretely arranged adhesive portions.
  • an air layer is formed between the optical layer laminate and the phosphor layer.
  • the occupied area ratio of the plurality of bonding portions in the first bonding layer is 50% or less.
  • the optical layer laminate has a light diffusion layer.
  • the light diffusion layer is formed closest to the phosphor layer among the layers included in the optical layer laminate.
  • the optical layer laminate has a polarization selective reflection layer.
  • the light diffusion layer is disposed closer to the LED substrate than the polarization selective reflection layer.
  • the optical layer laminate has at least one prism sheet.
  • the at least one prism sheet includes two prism sheets arranged such that the ridge lines of each prism are substantially orthogonal to each other.
  • the optical layer laminate includes two prism sheets arranged such that ridges of respective prisms are substantially orthogonal to each other, and a polarization selective reflection layer arranged on the two prism sheets. And the surface of the prism sheet closer to the phosphor layer facing the LED substrate among the two prism sheets is a mirror surface.
  • the surface of the optical layer laminate facing the LED substrate is a mirror surface.
  • no light diffusion layer is provided between the LED substrate and the wavelength selective reflection layer.
  • the plurality of adhesive layers include two or more adhesive layers formed between the optical layer laminate and the phosphor layer, and the first adhesive layer includes the two or more adhesive layers. Of the layers, it is located closest to the optical layer stack.
  • a reflection member that reflects the fluorescence and the excitation light is not provided in a region between the plurality of LED chips on the surface of the LED substrate.
  • an absorption member for absorbing the fluorescence is provided in a region between the plurality of LED chips on the surface of the LED substrate.
  • the phosphor includes a quantum dot phosphor.
  • the plurality of LED chips are bare-chip mounted on the LED substrate, and are arranged in a matrix at a pitch of 20 mm or less.
  • D / P is 0.8 or more.
  • a distance between the surface of the LED substrate and the wavelength selective reflection layer is 5 mm or less.
  • a manufacturing method is a method of manufacturing any one of the above-described liquid crystal display devices, comprising: a step A of preparing the liquid crystal display panel; and after the step A, the method of manufacturing the liquid crystal display panel.
  • the step B includes a step B1 of integrally fixing the phosphor layer and the wavelength selective reflection layer, and a step B2 of fixing the optical layer laminate on the back surface of the liquid crystal display panel. And a step B3 of bonding the optical layer laminate and the phosphor layer after the steps B1 and B2.
  • the step B includes a step of fixing the optical layer laminate, the phosphor layer and the wavelength selective reflection layer integrally, and then fixing the optical layer laminate, the phosphor layer and the wavelength selective reflection layer to the rear surface of the liquid crystal display panel.
  • the step B includes a step of integrally fixing the phosphor layer and the wavelength selective reflection layer, and then integrating the phosphor layer and the optical layer laminate.
  • the step B includes a step of integrally fixing the optical layer laminate and the phosphor layer and then integrating the optical layer laminate with the wavelength selective reflection layer.
  • the step of bonding the optical layer laminate and the phosphor layer to each other is performed using a double-sided adhesive film having a base film and two adhesive layers formed on both sides of the base film.
  • the adhesive layer closer to the optical layer laminate among the two adhesive layers has a plurality of discretely arranged adhesive portions.
  • the step of adhering the optical layer laminate and the phosphor layer to each other includes disposing the optical layer laminate and the phosphor on both sides ss of an adhesive layer having a plurality of discretely arranged adhesive portions. Contacting the body layer.
  • the step of bonding the optical layer laminate and the phosphor layer to each other includes a step of applying an adhesive layer to one surface of the optical layer laminate and then integrating the phosphor layer with the phosphor layer.
  • the method further includes a step of providing an adhesive layer on one surface of the phosphor layer and then integrating the phosphor layer with the optical layer laminate.
  • the liquid crystal display device including the backlight device of the remote phosphor system, including the thickness reduction, and / or the mass productivity.
  • FIG. 1 is a cross-sectional view schematically illustrating a liquid crystal display device 100 according to an embodiment of the present invention.
  • FIG. 10 is a cross-sectional view schematically illustrating a liquid crystal display device 100R according to another embodiment of the present invention.
  • FIG. 2 is a schematic cross-sectional view of the liquid crystal display device 100, and is an enlarged view of a part of FIG.
  • FIG. 3 is a schematic cross-sectional view of the liquid crystal display device 100R, and is a diagram showing a part of FIG. 2 in an enlarged manner.
  • FIG. 11 is a cross-sectional view schematically illustrating a liquid crystal display device 100B according to still another embodiment of the present invention.
  • FIG. 6 is a schematic cross-sectional view of the liquid crystal display device 100B, and is an enlarged view showing a part of FIG. 9 is a graph showing evaluation results of an experimental example.
  • (A) is a sectional view schematically showing a backlight device 950 of Comparative Example 1
  • (b) is a sectional view schematically showing a liquid crystal display device 900 of Comparative Example 1 having the backlight device 950. is there.
  • (A) is a schematic diagram when partial driving is performed using the backlight device 950R of Comparative Example 2, and (b) is displayed on the liquid crystal display device 900R of Comparative Example 2 having the backlight device 950R.
  • FIG. 4 is a diagram schematically showing an image pattern to be performed.
  • (A) is a schematic diagram when partial driving is not performed using the backlight device 950R
  • (b) is a diagram schematically illustrating an image pattern displayed on the liquid crystal display device 900R. It is sectional drawing which shows typically the liquid crystal display device 900B of another comparative example.
  • the backlight device 950 of Comparative Example 1 illustrated here has, for example, the same structure as the backlight device described in Patent Document 1.
  • FIG. 8A is a cross-sectional view schematically illustrating a backlight device 950
  • FIG. 8B is a cross-sectional view schematically illustrating a liquid crystal display device 900 of Comparative Example 1 including the backlight device 950. is there.
  • the backlight device 950 includes an LED substrate 901, a plurality of light emitting elements 910 supported by the LED substrate 901, and a phosphor sheet 920 disposed apart from the plurality of light emitting elements 910. And a wavelength-selective reflective film (dichroic filter) 930 disposed between the phosphor sheet 920 and the plurality of light emitting elements 910.
  • the phosphor sheet 920 emits fluorescence when excited by the light emitted from the light emitting element 910.
  • the light emitting element 910 is, for example, a blue LED
  • the phosphor sheet 920 includes a phosphor that emits green fluorescence and a phosphor that emits red fluorescence.
  • the remote phosphor method since the phosphor sheet 920 is disposed apart from the light emitting element 910, deterioration of the phosphor due to heat generated by the light emitting element 910 can be suppressed.
  • the phosphor sheet 920 has, for example, a phosphor layer 921 and protective layers 922 and 923 provided on both sides of the phosphor layer 921.
  • the wavelength-selective reflection film 930 transmits at least a part of the wavelength region of the light emitted from the light emitting element 910 and reflects at least a part of the light (“fluorescence”) emitted from the phosphor sheet 920.
  • the wavelength-selective reflective film 930 transmits all of the light emitted from the light emitting element 910 and reflects all of the light emitted from the phosphor sheet 920.
  • the wavelength-selective reflection film 930 transmits light in the emission wavelength region of the blue LED (that is, blue) and reflects light in the wavelength region from green to red. As described below with reference to FIG.
  • the backlight device 950 includes the wavelength-selective reflective film 930, and thus can suppress color unevenness when performing partial driving.
  • the light emitted from the phosphor sheet may be referred to as “fluorescence”.
  • fluorescence includes fluorescence and phosphorescence in a narrow sense.
  • the backlight device 950 further includes a diffusion plate 940 between the plurality of light emitting elements 910 and the wavelength selective reflection film 930.
  • the diffusion plate 940 acts to increase the uniformity of the intensity distribution of light emitted from the plurality of light emitting elements 910 and reaching the wavelength-selective reflection film 930.
  • the ratio (D1 / P) of the distance D1 between the LED substrate 901 and the diffusion plate 940 to the pitch P of the plurality of light emitting elements 910 the uniformity of the intensity distribution can be improved. There is a problem that the device becomes thick.
  • the diffusion plate 940 is omitted, the distance between the LED substrate 901 and the wavelength-selective reflection film 930 may be increased, but the backlight device is further thickened.
  • the uniformity of the intensity distribution can be improved. There is a problem in that the thickness is increased and / or the array density of the LEDs cannot be increased.
  • a backlight device 950 including a phosphor sheet 920, a wavelength-selective reflective film 930, and the like is prepared, and the backlight device 950 and a liquid crystal display panel are combined. And a liquid crystal display device. Therefore, as schematically shown in a cross-sectional view of the liquid crystal display device 900 of Comparative Example 1 having the backlight device 950 in FIG. 8B, for example, a portion between the liquid crystal display panel 990 and the backlight device 950 is provided. A gap G of about 1 mm to 2 mm was provided. This is to prevent the optical sheet disposed on the liquid crystal display panel 990 side of the backlight device 950 and the optical sheet on the backlight device 950 side of the liquid crystal display panel 990 from being damaged by friction or the like.
  • FIG. 9A is a cross-sectional view schematically showing a backlight device 950R of Comparative Example 2.
  • the backlight device 950R is a direct-type backlight device of a remote phosphor type having no wavelength selective reflection film.
  • the backlight device 950R is different from the backlight device 950 of Comparative Example 1 in that the backlight device 950R does not include the wavelength-selective reflection film 930.
  • FIG. 9A when partial driving is performed using the backlight device 950R, color unevenness may occur.
  • the backlight device 950R has a lighting area Ron in which the light emitting element 910 is lit and a light extinguishing area Roff in which the light emitting element 910 is not lit when performing partial driving.
  • FIG. 9A is a cross-sectional view schematically showing a backlight device 950R of Comparative Example 2.
  • the backlight device 950R is a direct-type backlight device of a remote phosphor type having no wavelength selective reflection film.
  • FIG. 9B schematically shows an image pattern displayed on the liquid crystal display device 900R of Comparative Example 2 having the backlight device 950R.
  • FIG. 9B is a schematic diagram when the liquid crystal display panel of the liquid crystal display device 900R is viewed from the normal direction.
  • the surface of the LED substrate 901 may have a reflection sheet between the light-emitting elements 910 in order to increase luminance. Without the reflective sheet, sufficient luminance may not be obtained in some cases. When the reflection sheet is provided, the occurrence of color unevenness may be more remarkable.
  • the backlight device 950 of Comparative Example 1 shown in FIG. 8A has the wavelength-selective reflection film 930, the backlight device 950 is emitted backward from the phosphor sheet 920 (to the LED substrate 901 side), Light reflected by the substrate 901 can be suppressed from entering the phosphor sheet 920 in the light-off region. Thereby, it is possible to suppress color unevenness when performing partial driving.
  • Patent Literature 1 discloses a direct-type backlight device of a remote phosphor type that performs partial driving.
  • the problem that there is a limit to the reduction in thickness is not limited to the presence or absence of partial driving, and is a problem common to liquid crystal display devices including a remote phosphor type backlight device.
  • Embodiments of the present invention are not limited to the presence or absence of partial driving, and can be applied to a liquid crystal display device including a remote phosphor type backlight device.
  • the backlight device included in the liquid crystal display device according to the embodiment of the present invention is, for example, a direct type. An edge light type may be used.
  • FIG. 1 is a sectional view schematically showing a liquid crystal display device 100 according to an embodiment of the present invention.
  • the liquid crystal display device 100 includes a liquid crystal display panel 10 and a backlight device 50 that emits light toward the back surface 10r of the liquid crystal display panel 10.
  • the backlight device 50 includes an LED substrate 21 on which a plurality of LED chips 22 are arranged on a front surface 21s so as to emit excitation light toward the back surface 10r of the liquid crystal display panel 10, and a fluorescent light that emits fluorescent light when receiving the excitation light.
  • a phosphor layer 25 including a body, a wavelength selective reflection layer 28 disposed between the phosphor layer 25 and the LED substrate 21 and having a transmittance of excitation light higher than a transmittance of fluorescence, and a liquid crystal of the phosphor layer 25.
  • optical layer laminate 30 arranged on the display panel 10 side.
  • the optical layer laminate 30, the phosphor layer 25, and the wavelength selective reflection layer 28 are integrally fixed to the back surface 10r of the liquid crystal display panel 10 via a plurality of adhesive layers 40a, 40b, and 40c.
  • the optical layer laminate 30, the phosphor layer 25, and the wavelength selective reflection layer 28 are integrally fixed to the back surface 10r of the liquid crystal display panel 10 via a plurality of adhesive layers 40a, 40b, and 40c. I have.
  • the optical layer stack 30, the phosphor layer 25, and the wavelength selective reflection layer 28 are supported by the liquid crystal display panel 10.
  • no gap is formed between the liquid crystal display panel 10 and the optical sheet disposed on the liquid crystal display panel 10 side of the backlight device 50. It can be thinner than the device.
  • the liquid crystal display device 100 does not include a light diffusion layer (for example, a light diffusion plate) between the LED substrate 21 and the wavelength selective reflection layer 28, the thickness can be further reduced.
  • the optical layer laminate 30 is provided to effectively irradiate the fluorescent light emitted from the phosphor layer 25 to the liquid crystal display panel 10 or to protect the phosphor layer 25.
  • the optical layer stack 30 includes at least one optical layer.
  • the optical layer may be a protective layer or an adhesive layer.
  • the optical layer laminate preferably includes a functional optical layer as exemplified below. However, the configuration of the optical layer laminate is not limited to the illustrated one.
  • the optical layer laminate 30 includes two prism sheets 34a and 34b, and a polarization selective reflection layer 32 disposed thereon.
  • the two prism sheets 34a and 34b are arranged such that the ridges of the respective prisms are substantially orthogonal to each other.
  • Each of the prism sheets 34a and 34b has, for example, a base film 34ba or 34bb, and a prism layer 34pa or 34pb formed on the base film 34ba or 34bb, respectively.
  • the prism sheets 34a and 34b for example, BEF manufactured by 3M can be used.
  • the polarization selective reflection layer 32 is, for example, an optical multilayer film having a laminated structure in which films having different refractive indexes are laminated.
  • DBEF registered trademark
  • 3M the polarization selective reflection layer 32
  • the surface facing the LED substrate 21 of the prism sheet 34b closer to the phosphor layer 25 is a mirror surface.
  • the plurality of adhesive layers 40a, 40b and 40c include the first adhesive layer 40a formed between the optical layer laminate 30 and the phosphor layer 25.
  • the first adhesive layer 40a has a plurality of discretely arranged adhesive portions 40p, and forms an air layer between the optical layer laminate 30 and the phosphor layer 25.
  • the luminance can be improved by the structure of the first adhesive layer 40a provided on the liquid crystal display panel 10 side of the phosphor layer 25. That is, since the first adhesive layer 40a has a plurality of adhesive portions 40p arranged discretely and forms an air layer between the optical layer laminate 30 and the phosphor layer 25, For example, it was found that the luminance can be improved (compared to the liquid crystal display device 100R shown in FIG. 2).
  • the first adhesive layer 40a is included in, for example, a double-sided adhesive film including a base film (for example, a PET film) and two adhesive layers formed on both sides of the base film.
  • a base film for example, a PET film
  • the other of the two adhesive layers may be an adhesive layer continuously formed on the entire surface of the base film.
  • Optional protective layers 26a and 26b may be provided on both sides of the phosphor layer 25.
  • the wavelength selective reflection layer 28 and the phosphor layer 25 (or the protection layer 26b provided on the LED substrate 21 side of the phosphor layer 25) are bonded to each other via, for example, a second adhesive layer 40b.
  • the liquid crystal display panel 10 includes the liquid crystal cell 1 and polarizing plates 11a and 11b provided on both sides of the liquid crystal cell 1.
  • the polarizing plates 11a and 11b are attached to the liquid crystal cell 1 via, for example, adhesive layers 40d and 40e, respectively.
  • the liquid crystal display panel included in the liquid crystal display device 100 is not limited to the illustrated example, and may be a known liquid crystal display panel.
  • FIG. 2 shows another example of the embodiment of the present invention.
  • FIG. 2 is a cross-sectional view schematically illustrating the liquid crystal display device 100R.
  • the liquid crystal display device 100R is configured such that the first adhesive layer 40R is formed so as to overlap substantially the entire surface of the phosphor layer 25 when viewed from the normal direction of the liquid crystal display panel 10. This is different from the liquid crystal display device 100 shown in FIG. That is, the first adhesive layer 40R of the liquid crystal display device 100R does not include a plurality of discretely arranged adhesive portions, and does not form an air layer between the optical layer laminate 30 and the phosphor layer 25.
  • liquid crystal display device 100R similarly to the liquid crystal display device 100 shown in FIG. 1, no gap is formed between the optical sheet disposed on the liquid crystal display panel 10 side of the backlight device 50 and the liquid crystal display panel 10. , And can be thinner than a conventional liquid crystal display device. Further, since the liquid crystal display device 100R does not have the light diffusion layer between the LED substrate 21 and the wavelength selective reflection layer 28, the thickness can be further reduced.
  • the liquid crystal display device 100 shown in FIG. 1 can improve the luminance as compared with the liquid crystal display device 100R. This will be described with reference to FIGS. The following is a consideration of the present inventors and does not limit the present invention.
  • FIGS. 3 and 4 are schematic sectional views of the liquid crystal display device 100 and the liquid crystal display device 100R, respectively. 3 and 4 schematically show a part of FIGS. 1 and 2 in an enlarged manner, respectively.
  • the excitation light La emitted from the LED chip 22 toward the rear surface 10r of the liquid crystal display panel 10 enters the phosphor layer 25.
  • the phosphor layer 25 includes a phosphor 25q that receives the excitation light La and emits the fluorescence Lb.
  • the fluorescence Lb includes fluorescence and phosphorescence in a narrow sense.
  • the phosphor layer 25 includes a quantum dot phosphor 25q dispersed in a resin.
  • a part of the excitation light La is reflected on the interface between the protective layer 26a and the air layer formed by the first adhesive layer 40a, and then enters the phosphor layer 25 again. Thereby, the utilization efficiency of the excitation light can be improved.
  • the excitation light La is also reflected at the interface between the air layer formed by the first adhesive layer 40a and the prism sheet 34b, and reenters the phosphor layer 25.
  • the utilization efficiency of the excitation light is high, the luminance can be improved as compared with the liquid crystal display device 100R.
  • the reflection of the excitation light La at the interface between the protective layer 26a and the first adhesive layer 40R is suppressed. This is because the difference between the refractive index of the protective layer 26a and the refractive index of the first adhesive layer 40R is smaller than the difference between the refractive index a of the protective layer 26a and the refractive index of the air layer. Similarly, the reflection of the excitation light La is suppressed at the interface between the first adhesive layer 40R and the prism sheet 34b.
  • the difference between the refractive index of the first adhesive layer 40R and the refractive index of the prism sheet 34b is determined by the refractive index of the air layer and the refractive index of the prism sheet 34b (the base of the prism sheet 34b). This is because it is smaller than the difference from the refractive index of the film 34bb). Therefore, the utilization efficiency of the excitation light is lower than that of the liquid crystal display device 100.
  • the excitation light La emitted from the phosphor layer 25 causes an interface between these layers. And is incident on the prism sheet 34b without being reflected.
  • the occupied area ratio of the plurality of bonding portions 40p in the first bonding layer 40a is preferably small, for example, 50% or less from the viewpoint of improving the utilization efficiency of the excitation light. Considering the mechanical strength of the backlight device 50, it is preferably large, for example, 50% or more.
  • the size of each of the bonded portions 40p (refers to the area circle equivalent diameter, for example, the diameter (dot diameter) when the bonded portion 40p is substantially circular) is, for example, about 300 ⁇ m to 600 ⁇ m. If it is smaller than this, there is a possibility that some of the bonding portions 40p may be missing. It is preferable to adjust the size, pitch, and arrangement direction of the bonding portion 40p so as not to interfere with the periodic structure of the pixel array.
  • the first adhesive layer 40a is formed, for example, using an optically clear adhesive that is optically transparent and does not scatter.
  • the excitation light It is considered that the usage efficiency can be improved, and thereby the brightness of the liquid crystal display device can be improved.
  • the structure of the optical layer laminate 30 is not limited to the illustrated one.
  • the layer closest to the phosphor layer 25 may be a prism sheet, or a polarization selective reflection layer, a polarization layer, a light diffusion layer, a transparent sheet, a protective layer, and the like. It can be any layer.
  • the present invention is not limited to the first adhesive layer 40a forming the air layer shown in FIG. May be provided on the liquid crystal display panel 10 side of the protective layer 26a) provided on the liquid crystal display panel 10 side.
  • the first adhesive layer 40a and the light diffusion layer may be used together, or a light diffusion layer may be provided instead of the first adhesive layer 40a.
  • the light diffusion layer is preferably formed closest to the phosphor layer 25 among the optical layers constituting the optical layer laminate.
  • the phosphor layer 25 includes the quantum dot phosphor 25q has been described, but the embodiment of the present invention is not limited to this.
  • the effect that the utilization efficiency of the excitation light can be improved is not limited to this case.
  • the configuration of the liquid crystal display device 100 (particularly, the configuration of the backlight device 50) will be described more specifically.
  • the backlight device 50 is of a remote phosphor type in which a phosphor (phosphor layer 25) is arranged apart from the light emitting element (LED chip 22).
  • the LED chip 22 and the phosphor layer 25 emit white light toward the back surface 10r of the liquid crystal display panel 10.
  • the light emitted from the LED chip 22 excites the phosphor in the phosphor layer 25 to emit light (fluorescence or phosphorescence).
  • the phosphor layer 25 may include a phosphor that emits green fluorescence and / or a phosphor that emits red fluorescence, or emits yellow fluorescence.
  • a phosphor may be included.
  • the phosphor layer 25 preferably contains a phosphor that emits green fluorescence and / or a phosphor that emits red fluorescence.
  • the phosphor layer 25 may include, for example, a quantum dot phosphor that emits green fluorescence and / or a quantum dot phosphor that emits red fluorescence.
  • Quantum dot phosphors generally have the advantage that the half width of the peak wavelength of the emission spectrum is narrow and the color purity is high, and therefore, for example, satisfy the UHD @ Premium standard (color reproducibility BT2020 standard 90% or more, HDR10 standard). It has been shown to be promising.
  • a known phosphor such as a red sulfide phosphor (for example, calcium sulfide phosphor) and a green sulfide phosphor (for example, thiogallate phosphor) may be used.
  • the thickness of the phosphor layer 25 and the protective layers 26a, 26b is, for example, about 100 ⁇ m, respectively, and the sum of the thicknesses of the phosphor layer 25 and the protective layers 26a, 26b is, for example, about 300 ⁇ m.
  • the wavelength selective reflection layer (dichroic filter) 28 transmits at least a part of the wavelength region of the light emitted from the LED chip 22 and at least a part of the light (fluorescence or phosphorescence) emitted from the phosphor layer 25. Is reflected.
  • the wavelength selective reflection layer 28 transmits all of the light emitted from the LED chip 22 and reflects all of the light emitted from the phosphor layer 25.
  • the wavelength selective reflection layer 28 transmits light in the emission wavelength region (that is, blue) of the blue LED and reflects light in the wavelength region from green to red.
  • the wavelength selective reflection layer 28 is, for example, an optical multilayer film having a laminated structure in which films having different refractive indexes are laminated.
  • the liquid crystal display device 100 includes the wavelength selective reflection layer 28, color unevenness can be suppressed both when the partial driving is performed and when the partial driving is not performed.
  • the plurality of LED chips 22 of the liquid crystal display device 100 may or may not be partially driven.
  • partial driving similarly to the backlight device 950 of Comparative Example 1, it is possible to suppress color unevenness that occurs in the backlight device 950R of Comparative Example 2 described with reference to FIG. A case in which the partial drive is not performed will be described below with reference to FIG.
  • FIG. 10A when the backlight device 950R of Comparative Example 2 is used, color unevenness may occur even when partial driving is not performed.
  • FIG. 10B schematically shows an image pattern displayed when white display is performed on the entire surface of the liquid crystal display device 900R of Comparative Example 2.
  • FIG. 10B is a schematic view when the liquid crystal display panel of the liquid crystal display device 900R is viewed from the normal direction.
  • the light for L b is high, and thus the probability to excite the phosphor in the phosphor sheet 920 than the light L a, emits more light in the wavelength region of toward green from red. Therefore, when viewed from the normal direction of the liquid crystal display panel, yellowish color becomes strong in a region around the light emitting element 910.
  • the liquid crystal display device 100 since the liquid crystal display device 100 has the wavelength selection reflection layer 28, light emitted from the phosphor layer 25 backward (toward the LED substrate 21) is reflected by the wavelength selection reflection layer 28, and It is emitted toward the back surface 10r of 10. As a result, when viewed from the normal direction of the liquid crystal display panel 10, light in a wavelength region from red to green is enhanced in a region overlapping the LED chip 22. Therefore, the difference in tint between the area overlapping the LED chip 22 and the surrounding area is reduced, and color unevenness is reduced.
  • the liquid crystal display device 100 has an effect of reducing color unevenness when partial driving is not performed even when the first adhesive layer 40a forms an air layer. By improving the utilization efficiency of the excitation light, the emission of the red and green fluorescent light is enhanced in the region overlapping the LED chip 22.
  • the LED chip 22 may emit magenta light. That is, the LED chip 22 may have a structure in which a dispersion medium (resin) in which a red phosphor is dispersed is provided on the light emitting surface of the blue LED chip.
  • a dispersion medium resin
  • the blue light emitted from the blue LED chip excites the red phosphor to emit red light.
  • the entire LED chip 22 emits blue light and red light, and appears to emit magenta light.
  • the phosphor layer 25 only needs to include a green phosphor, and the wavelength selective reflection layer 28 only needs to transmit blue and red light and reflect green light.
  • the plurality of LED chips 22 are arranged in a matrix on the surface 21s of the LED substrate 21, for example.
  • the LED board 21 may serve as, for example, a chassis, and the liquid crystal display device 100 may further include a chassis (not shown).
  • the plurality of LED chips 22 may be mounted on the LED substrate 21 as bare chips. That is, each of the LED chips 22 may not be covered with the optical lens. When a plurality of LED chips 22 are mounted as bare chips, the following advantages can be obtained.
  • each of the plurality of light emitting elements (for example, LED chips) 910 is often covered with an optical lens in order to obtain desired light distribution characteristics.
  • the minimum diameter of the optical lens is about 10 mm due to design restrictions. Therefore, for example, if the pitch of the plurality of light emitting elements 910 covered by the optical lens is twice the lens diameter of the optical lens, the pitch P of the plurality of light emitting elements 910 is at least about 20 mm. Then, in order to set D1 / P to 0.25 or more, the distance D1 between the LED substrate 901 and the diffusion plate 940 cannot be made smaller than 5 mm. Since the thickness of the diffusion plate 940 is generally several mm, the thickness of the backlight device 950 is limited.
  • the surface of the LED substrate 901 may have a reflective sheet between the light-emitting elements 910 in order to increase luminance.
  • the distance between the phosphor sheet 920 and the plurality of light emitting elements 910 is 10 mm or more from the viewpoint of suppressing luminance unevenness and suppressing the influence of heat on the phosphor sheet 920. It is stated that it is desirable.
  • the LED chips 22 of the liquid crystal display device 100 are bare-chip mounted on the LED substrate 21 (that is, if a plurality of bare LED chips 22 are arranged on the surface 21s of the LED substrate 21),
  • the pitch P between the plurality of LED chips 22 can be set to 20 mm or less. This makes it possible to reduce the distance D between the LED substrate 21 and the wavelength selective reflection layer 28 to 5 mm or less while suppressing the occurrence of uneven brightness.
  • the liquid crystal display device 100 can be made thinner than the liquid crystal display device 900 of Comparative Example 1, while suppressing the occurrence of uneven brightness.
  • the liquid crystal display device 100 by reducing the pitch P between the plurality of LED chips 22 to 20 mm or less, the distance D between the LED substrate 21 and the wavelength selective reflection layer 28 with respect to the pitch P between the plurality of LED chips 22 is reduced. It was found that when the ratio (D / P) was 0.8 or more, it was possible to sufficiently suppress luminance unevenness and color unevenness. That is, the liquid crystal display device 100 is sufficiently provided without having a light diffusion layer between the LED substrate 21 and the wavelength selective reflection layer 28, a reflection member on the surface 21s of the LED substrate 21, and an optical lens covering the LED chip 22. It was found that uneven brightness and uneven color can be suppressed.
  • the “reflecting member” is defined as a member having a total light reflectance (the sum of the regular reflectance and the diffuse reflectance) of 80% or more in a hemispherical region having a light receiving angle of 2 ⁇ steradian in an incident angle range of 0 ° to 45 °. I will say.
  • Such total light reflectance can be measured using, for example, a scattering / appearance measurement system IS-SA manufactured by RADIANT. Since the backlight device 50 has the wavelength selective reflection layer 28, the influence of the decrease in luminance due to the absence of the reflection member is small.
  • An absorbing member that absorbs fluorescence may be provided between the plurality of LED chips 22 on the surface 21s of the LED substrate 21.
  • the absorbing member By providing the absorbing member, it becomes easy to suppress the color unevenness at the time of the partial driving that occurs in the backlight device 950R of Comparative Example 2 described with reference to FIG. That is, light emitted backward from the phosphor layer 25 (on the side of the LED substrate 21) is reflected by the surface 21s of the LED substrate 21, and the amount of light incident on the phosphor layer 25 again decreases, so that the effect is reduced. It is.
  • FIG. 5 shows still another example of the embodiment of the present invention.
  • FIG. 5 is a cross-sectional view schematically showing a liquid crystal display device 100B having an optical layer laminate 30B.
  • the liquid crystal display device 100B differs from the liquid crystal display device 100 in having an optical layer laminate 30B.
  • the optical layer laminate 30B differs from the optical layer laminate 30 in further including a light diffusion layer 36.
  • the light diffusion layer 36 is disposed closer to the LED substrate 21 than the polarization selective reflection layer 32 is.
  • the light diffusion layer 36 has, for example, a base film (for example, a PET film) 36b and a light diffusion material (for example, spherical beads) 36d provided on the base film 36b.
  • the surface of the prism sheet 34b closer to the phosphor layer 25 facing the LED substrate 21 is a mirror surface.
  • liquid crystal display device 100B similarly to the liquid crystal display device 100 shown in FIG. 1, no gap is formed between the liquid crystal display panel 10 and the optical sheet disposed on the liquid crystal display panel 10 side of the backlight device 50. , And can be thinner than a conventional liquid crystal display device. Further, since the liquid crystal display device 100B does not have the light diffusion layer between the LED substrate 21 and the wavelength selective reflection layer 28, the thickness can be further reduced.
  • the liquid crystal display device 100B can also improve the luminance as compared with the liquid crystal display device 100R, like the liquid crystal display device 100 described with reference to FIG. This will be described with reference to FIG.
  • FIG. 6 is a schematic cross-sectional view of the liquid crystal display device 100B, and is an enlarged view of a part of FIG.
  • the method for manufacturing the liquid crystal display device 100 includes, for example, the following steps.
  • Step I A liquid crystal display panel 10 is prepared.
  • Step II After step I, the optical layer laminate 30, the phosphor layer 25, and the wavelength selective reflection layer 28 are integrally fixed on the back surface 10r of the liquid crystal display panel 10 via the plurality of adhesive layers 40a, 40b, and 40c. I do.
  • Step III Prepare an LED substrate 21 on which a plurality of LED chips 22 are arranged on the front surface 21s.
  • Step IV After the steps II and III, the liquid crystal display panel 10 and the LED substrate 21 are fixed so that the plurality of LED chips 22 face the rear surface 10r of the liquid crystal display panel 10.
  • Step II includes, for example, the following steps.
  • Step IIa The phosphor layer 25 and the wavelength selective reflection layer 28 are integrally fixed.
  • Step IIb The optical layer laminate 30 is fixed on the back surface 10r of the liquid crystal display panel 10.
  • Step IIc After the step IIa and the step IIb, the optical layer laminate 30 and the phosphor layer 25 are bonded. In this case, the manufacturing cost of the liquid crystal display device 100 may be reduced in some cases. In a factory that manufactures the liquid crystal display device 100 having the phosphor layer 25 and the liquid crystal display device having no phosphor layer, if the above manufacturing process is adopted, the step IIc is performed only when the liquid crystal display device 100 is manufactured. Since it suffices to perform the process, the production management can be performed efficiently.
  • the step II may include a step of fixing the optical layer laminate 30, the phosphor layer 25, and the wavelength selective reflection layer 28 integrally, and then fixing them to the rear surface 10r of the liquid crystal display panel 10.
  • the phosphor layer 25 and the wavelength selective reflection layer 28 may be integrated with the optical layer laminate 30, or the optical layer laminate 30 and the phosphor layer 25 may be integrally fixed. After that, it may be integrated with the wavelength selective reflection layer 28.
  • the step of bonding the optical layer laminate 30 and the phosphor layer 25 to each other is performed using, for example, a double-sided adhesive film having a base film and two adhesive layers formed on both sides of the base film.
  • a double-sided adhesive film having a base film and two adhesive layers formed on both sides of the base film.
  • the assembly process can be simplified.
  • One of the two adhesive layers formed on both sides of the base film is a first adhesive layer (dot adhesive layer) 40a, and the other is an adhesive layer continuously formed on the entire surface of the base film.
  • the adhesive layer closer to the optical layer laminate 30 of the two adhesive layers is the first adhesive layer 40a, that is, the adhesive layer having a plurality of discretely arranged adhesive portions 40p, the light use efficiency is improved. (E.g., more than the reverse arrangement).
  • the step of bonding the optical layer laminate 30 and the phosphor layer 25 to each other may be performed without using a double-sided adhesive film.
  • the step of adhering the optical layer laminate 30 and the phosphor layer 25 to each other includes the above-mentioned first adhesive layer 40a, that is, an optical layer on both sides of an adhesive layer having a plurality of discretely arranged adhesive portions 40p.
  • a step of bringing the laminate 30 and the phosphor layer 25 into contact may be included.
  • the adhesive layer may be provided on one surface of the optical layer laminate 30 and then integrated with the phosphor layer 25 or the phosphor layer 25 may be integrated. After the adhesive layer is provided on one surface, the adhesive layer may be integrated with the optical layer laminate 30.
  • Example 1 has the same structure as the liquid crystal display device 100 shown in FIG. 1
  • Examples 2 and 3 have the same structure as the liquid crystal display device 100B shown in FIG. It has the same structure as the liquid crystal display device 100R shown in FIG.
  • Embodiments 2 and 3 differ in the pitch and size of the bonding portion 40p of the first bonding layer 40a.
  • the fourth embodiment differs from the first embodiment in having a first adhesive layer 40R in which no air layer is formed.
  • the comparative example has the same structure as the liquid crystal display device 900B shown in FIG.
  • the backlight device 950B included in the liquid crystal display device 900B (comparative example) is different from the backlight device 950 included in the liquid crystal display device 900 illustrated in FIG.
  • the optical layer laminate 960 has a structure similar to that of the optical layer laminate 30 included in the liquid crystal display device 100 shown in FIG. 1, and includes two prism sheets 964a and 964b and a polarization selector disposed thereon.
  • a reflective layer 962 is a structure similar to that of the optical layer laminate 30 included in the liquid crystal display device 100 shown in FIG. 1, and includes two prism sheets 964a and 964b and a polarization selector disposed thereon.
  • an adhesive is provided between the optical layer laminate 960 and the phosphor sheet 920, between the phosphor sheet 920 and the wavelength-selective reflective film 930, and between the wavelength-selective reflective film 930 and the diffusion plate 940.
  • No layers are arranged and air layers S1, S2 and S3 are each formed. That is, on the diffusion plate 940, the wavelength-selective reflection film 930, the phosphor sheet 920, and the optical layer laminate 960 are stacked and placed in this order.
  • the liquid crystal display panel 990 includes a liquid crystal cell 991 and polarizing plates 992a and 992b provided on both sides of the liquid crystal cell 991.
  • Polarizing plate 11a (with protective laminate, thickness 230 ⁇ m) Liquid crystal cell 1 (1200 ⁇ m thickness, transmittance of glass substrate 1.49) Polarizing plate 11b (without protective laminate, thickness 166 ⁇ m)
  • Optical layer laminate 30 GD221 manufactured by GLOTEC (DPOP: Optical composite function sheet) Thickness of optical layer laminate 30: 380 ⁇ m
  • First adhesive layer 40a TN20AIR manufactured by DIC Corporation
  • the pitch of the plurality of bonding portions 40p is 800 ⁇ m, and the dot diameter of the bonding portions 40p is 300 ⁇ m.
  • Occupied area ratio of the plurality of bonding portions 40p in the first bonding layer 40a 50% Refractive index of first adhesive layer 40a: about 1.49
  • Thickness of first adhesive layer 40a 25 ⁇ m
  • Phosphor layer 25 and protective layers 26a and 26b quantum dot film manufactured by Hitachi Chemical Co., Ltd. Sum of thicknesses of phosphor layer 25 and protective layers 26a and 26b: 360 ⁇ m
  • Wavelength-selective reflective layer 28 Picasus sheet manufactured by Toray Industries, Inc. Thickness of wavelength-selective reflective layer 28: 70 ⁇ m Protective layer (thickness 60 ⁇ m)
  • Optical layer laminate 30B (in order from the liquid crystal display panel 10 side) Diffusion adhesive layer (PSA (pressure-sensitive adhesive)) (50 ⁇ m thickness) DBEF-QV2 (core) (92 ⁇ m thick) PET film: thickness 50 ⁇ m, refractive index 1.58 Prism layer 34pa of prism sheet 34a: + 45 ° 60P, acrylic resin, thickness 35 ⁇ m, refractive index 1.56
  • Base film 34ba of prism sheet 34a PET film, thickness 50 ⁇ m, refractive index 1.58 Prism layer 34pb of prism sheet 34b: ⁇ 45 ° 60P, acrylic resin, thickness 35 ⁇ m, refractive index 1.56
  • Base film 34bb of prism sheet 34b PET film, thickness 50 ⁇ m, refractive index 1.58
  • Light diffusing material (beads) 36d of the light diffusing layer 36 thickness 30 ⁇ m, refractive index of about 1.43 to 1.66
  • Example 3 (except for the following, which is the same as Example 2)
  • First adhesive layer 40a TN06AIR manufactured by DIC Corporation Pitch 580 ⁇ m of plural bonding parts 40p, dot diameter 220 ⁇ m of bonding parts 40p Occupied area ratio of the plurality of bonding portions 40p in the first bonding layer 40a: 50%
  • Table 1 and FIG. 7 show the evaluation results of Examples 1 to 4 and Comparative Example.
  • a gap G of about 3 mm is provided between the liquid crystal display panel 990 and the backlight device 950B.
  • the liquid crystal display panel and the backlight device optical layer laminate
  • the liquid crystal display panel and the backlight device are not bonded to each other.
  • the backlight device 950B of the comparative example has a diffusion plate 940 (thickness Dd: 2 mm)
  • the backlight devices 950B of Examples 1 to 4 each include a diffusion plate between the LED substrate and the wavelength selective reflection layer. Do not have. Therefore, Examples 1 to 4 could be made at least about 5 mm thinner than the Comparative Example.
  • Examples 1 to 3 having the first adhesive layer 40a forming the air layer are all different from Examples 4 having the first adhesive layer 40R not forming the air layer. Also exhibited high brightness.
  • the embodiment of the present invention is suitably used as a liquid crystal display device having an LED backlight.

Abstract

A liquid crystal display device (100) according to the present invention is provided with a liquid crystal display panel (10) and a backlight device (50) which emits light toward the back surface (10r) of the liquid crystal display panel. The backlight device comprises: an LED substrate (21) that has a front surface (21s) on which a plurality of LED chips (22) are arranged so as to emit excitation light toward the back surface of the liquid crystal display panel; a phosphor layer (25) which contains a phosphor (25q) that emits fluorescent light upon reception of the excitation light; a wavelength selective reflection layer (28) which is arranged between the phosphor layer and the LED substrate, and wherein the transmittance of the excitation light is higher than the transmittance of the fluorescent light; and an optical layer laminate (30) which is arranged on the liquid crystal display panel side of the phosphor layer. The optical layer laminate, the phosphor layer and the wavelength selective reflection layer are affixed to the back surface of the liquid crystal display panel in an integrated manner, with a plurality of adhesive layers including a first adhesive layer (40a) being interposed therebetween.

Description

液晶表示装置およびその製造方法Liquid crystal display device and method of manufacturing the same
　本発明は、液晶表示装置およびその製造方法に関し、特にＬＥＤバックライトを備える液晶表示装置およびその製造方法に関する。 The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly, to a liquid crystal display device having an LED backlight and a method for manufacturing the same.
　現在市販されている液晶表示装置の多くは、複数のＬＥＤを備えたバックライト装置を備えている。複数のＬＥＤは、例えば、複数の領域に分割され、照明光が必要な領域のＬＥＤだけ点灯される、あるいは、領域ごとに必要とされる輝度に調整される。バックライトのこのような駆動方法は、分割駆動、部分駆動、エリア駆動またはローカルディミングと呼ばれる。分割駆動法を採用すると、液晶表示装置の明部と暗部との輝度のコントラスト比を向上させることができる。 Many liquid crystal display devices currently on the market are equipped with a backlight device having a plurality of LEDs. The plurality of LEDs are divided into, for example, a plurality of regions, and only the LEDs in the region where illumination light is required are turned on, or the brightness is adjusted to the required luminance for each region. Such a driving method of the backlight is called divided driving, partial driving, area driving, or local dimming. When the division driving method is employed, the contrast ratio of the brightness between the bright part and the dark part of the liquid crystal display device can be improved.
　近年、表示装置の表示品位を向上させるために、ハイダイナミックレンジ（High Dynamic Range、以下「ＨＤＲ」という。）に対応した液晶表示装置が市販されるに至っている。 In recent years, in order to improve the display quality of a display device, a liquid crystal display device compatible with a high dynamic range (High Dynamic Range, hereinafter referred to as “HDR”) has been marketed.
　さらに、ＵＨＤ　Ｐｒｅｍｉｕｍ規格（色再現性ＢＴ２０２０規格９０％以上、ＨＤＲ１０規格）に対応可能な液晶表示装置として、特許文献１および２に記載されているように、リモートフォスファー方式を採用し、かつ、ダイクロイック・フィルタを用いて色むらを抑制する液晶表示装置が検討されている。 Further, as described in Patent Literatures 1 and 2, a remote phosphor method is adopted as a liquid crystal display device capable of complying with the UHD @ Premium standard (color reproduction BT2020 standard 90% or more, HDR10 standard), and A liquid crystal display device that suppresses color unevenness using a dichroic filter has been studied.
特開２０１７－８４７６１号公報JP-A-2017-84761 特開２００７－８１２３４号公報JP 2007-81234 A
　本発明は、リモートフォスファー方式のバックライト装置を備えた液晶表示装置の薄型化を含む性能の向上および／または量産性を向上させることを目的とする。 The object of the present invention is to improve the performance of a liquid crystal display device including a backlight device of a remote phosphor type, including thinning, and / or to improve the mass productivity.
　本発明のある実施形態による液晶表示装置は、液晶表示パネルと、前記液晶表示パネルの背面に向けて光を出射するバックライト装置とを備える液晶表示装置であって、前記バックライト装置は、前記液晶表示パネルの前記背面に向けて励起光を出射するように複数のＬＥＤチップが表面に配列されたＬＥＤ基板と、前記励起光を受けて、蛍光を発する蛍光体を含む蛍光体層と、前記蛍光体層と前記ＬＥＤ基板との間に配置され、前記励起光の透過率が前記蛍光の透過率よりも高い波長選択反射層と、前記蛍光体層の前記液晶表示パネル側に配置された光学層積層体とを有し、前記光学層積層体、前記蛍光体層および前記波長選択反射層は、前記液晶表示パネルの前記背面に、第１接着層を含む複数の接着層を介して一体に固定されている。 A liquid crystal display device according to an embodiment of the present invention is a liquid crystal display device including a liquid crystal display panel and a backlight device that emits light toward the back of the liquid crystal display panel, wherein the backlight device is An LED substrate having a plurality of LED chips arranged on a surface thereof so as to emit excitation light toward the rear surface of the liquid crystal display panel; a phosphor layer containing a phosphor that receives the excitation light and emits fluorescence; A wavelength selective reflection layer disposed between the phosphor layer and the LED substrate, wherein the transmittance of the excitation light is higher than the transmittance of the fluorescence; and an optical element disposed on the liquid crystal display panel side of the phosphor layer. Wherein the optical layer laminate, the phosphor layer, and the wavelength selective reflection layer are integrally formed on the back surface of the liquid crystal display panel via a plurality of adhesive layers including a first adhesive layer. Fixed
　ある実施形態において、前記第１接着層は、前記光学層積層体と前記蛍光体層との間に形成されており、前記第１接着層は、離散的に配置された複数の接着部を有し、かつ、前記光学層積層体と前記蛍光体層との間に空気層を形成している。 In one embodiment, the first adhesive layer is formed between the optical layer laminate and the phosphor layer, and the first adhesive layer has a plurality of discretely arranged adhesive portions. In addition, an air layer is formed between the optical layer laminate and the phosphor layer.
　ある実施形態において、前記第１接着層における前記複数の接着部の占有面積率は５０％以下である。 In one embodiment, the occupied area ratio of the plurality of bonding portions in the first bonding layer is 50% or less.
　ある実施形態において、前記光学層積層体は、光拡散層を有する。 In one embodiment, the optical layer laminate has a light diffusion layer.
　ある実施形態において、前記光拡散層は、前記光学層積層体に含まれる層のうち、前記蛍光体層の最も近くに形成されている。 In one embodiment, the light diffusion layer is formed closest to the phosphor layer among the layers included in the optical layer laminate.
　ある実施形態において、前記光学層積層体は、偏光選択反射層を有する。 In one embodiment, the optical layer laminate has a polarization selective reflection layer.
　ある実施形態において、前記光拡散層は、前記偏光選択反射層よりも、前記ＬＥＤ基板の近くに配置されている。 In one embodiment, the light diffusion layer is disposed closer to the LED substrate than the polarization selective reflection layer.
　ある実施形態において、前記光学層積層体は、少なくとも１枚のプリズムシートを有する。 In one embodiment, the optical layer laminate has at least one prism sheet.
　ある実施形態において、前記少なくとも１枚のプリズムシートは、それぞれのプリズムの稜線が互いに略直交する様に配置された２枚のプリズムシートを含む。 In one embodiment, the at least one prism sheet includes two prism sheets arranged such that the ridge lines of each prism are substantially orthogonal to each other.
　ある実施形態において、前記光学層積層体は、それぞれのプリズムの稜線が互いに略直交する様に配置された２枚のプリズムシートと、前記２枚のプリズムシートの上に配置された偏光選択反射層とを有し、前記２枚のプリズムシートのうち、前記蛍光体層に近い方のプリズムシートの、前記ＬＥＤ基板を向く表面は鏡面である。 In one embodiment, the optical layer laminate includes two prism sheets arranged such that ridges of respective prisms are substantially orthogonal to each other, and a polarization selective reflection layer arranged on the two prism sheets. And the surface of the prism sheet closer to the phosphor layer facing the LED substrate among the two prism sheets is a mirror surface.
　ある実施形態において、前記光学層積層体の前記ＬＥＤ基板を向く表面は鏡面である。 In one embodiment, the surface of the optical layer laminate facing the LED substrate is a mirror surface.
　ある実施形態において、前記ＬＥＤ基板と前記波長選択反射層との間に光拡散層を有しない。 In one embodiment, no light diffusion layer is provided between the LED substrate and the wavelength selective reflection layer.
　ある実施形態において、前記複数の接着層は、前記光学層積層体と前記蛍光体層との間に形成された２以上の接着層を有し、前記第１接着層は、前記２以上の接着層のうち、前記光学層積層体の最も近くに配置されている。 In one embodiment, the plurality of adhesive layers include two or more adhesive layers formed between the optical layer laminate and the phosphor layer, and the first adhesive layer includes the two or more adhesive layers. Of the layers, it is located closest to the optical layer stack.
　ある実施形態において、前記ＬＥＤ基板の前記表面の、前記複数のＬＥＤチップの間の領域には、前記蛍光および前記励起光を反射する反射部材を有しない。 In one embodiment, a reflection member that reflects the fluorescence and the excitation light is not provided in a region between the plurality of LED chips on the surface of the LED substrate.
　ある実施形態において、前記ＬＥＤ基板の前記表面の、前記複数のＬＥＤチップの間の領域には、前記蛍光を吸収する吸収部材が設けられている。 In one embodiment, an absorption member for absorbing the fluorescence is provided in a region between the plurality of LED chips on the surface of the LED substrate.
　ある実施形態において、前記蛍光体は、量子ドット蛍光体を含む。 In one embodiment, the phosphor includes a quantum dot phosphor.
　ある実施形態において、前記複数のＬＥＤチップは、前記ＬＥＤ基板にベアチップ実装されており、かつ、２０ｍｍ以下のピッチでマトリクス状に配列されている。 In one embodiment, the plurality of LED chips are bare-chip mounted on the LED substrate, and are arranged in a matrix at a pitch of 20 mm or less.
　ある実施形態において、前記複数のＬＥＤチップの前記ピッチをＰ、前記ＬＥＤ基板の前記表面と前記波長選択反射層との間の距離をＤとすると、Ｄ／Ｐは０．８以上である。 In one embodiment, when the pitch between the plurality of LED chips is P and the distance between the surface of the LED substrate and the wavelength selective reflection layer is D, D / P is 0.8 or more.
　ある実施形態において、前記ＬＥＤ基板の前記表面と前記波長選択反射層との間の距離は５ｍｍ以下である。 In one embodiment, a distance between the surface of the LED substrate and the wavelength selective reflection layer is 5 mm or less.
　本発明のある実施形態による製造方法は、上記のいずれかの液晶表示装置を製造する方法であって、前記液晶表示パネルを用意する工程Ａと、前記工程Ａの後に、前記液晶表示パネルの前記背面上に、前記光学層積層体、前記蛍光体層および前記波長選択反射層を前記複数の接着層を介して一体に固定する工程Ｂと、前記複数のＬＥＤチップが前記表面に配列された前記ＬＥＤ基板を用意する工程Ｃと、前記工程Ｂおよび前記工程Ｃの後に、前記液晶表示パネルの前記背面に前記複数のＬＥＤチップが向くように、前記液晶表示パネルと前記ＬＥＤ基板とを固定する工程Ｄとを包含する。 A manufacturing method according to an embodiment of the present invention is a method of manufacturing any one of the above-described liquid crystal display devices, comprising: a step A of preparing the liquid crystal display panel; and after the step A, the method of manufacturing the liquid crystal display panel. A step B of integrally fixing the optical layer laminate, the phosphor layer, and the wavelength selective reflection layer via the plurality of adhesive layers on the back surface, and the plurality of LED chips being arranged on the surface; A step C of preparing an LED substrate, and a step of fixing the liquid crystal display panel and the LED substrate so that the plurality of LED chips face the rear surface of the liquid crystal display panel after the steps B and C. D.
　ある実施形態において、前記工程Ｂは、前記蛍光体層と前記波長選択反射層とを一体に固定する工程Ｂ１と、前記液晶表示パネルの前記背面上に、前記光学層積層体を固定する工程Ｂ２と、前記工程Ｂ１および工程Ｂ２の後に、前記光学層積層体と前記蛍光体層とを貼り合せる工程Ｂ３とを包含する。 In one embodiment, the step B includes a step B1 of integrally fixing the phosphor layer and the wavelength selective reflection layer, and a step B2 of fixing the optical layer laminate on the back surface of the liquid crystal display panel. And a step B3 of bonding the optical layer laminate and the phosphor layer after the steps B1 and B2.
　ある実施形態において、前記工程Ｂは、前記光学層積層体、前記蛍光体層および前記波長選択反射層を一体に固定した後、前記液晶表示パネルの前記背面に固定する工程を包含する。 In one embodiment, the step B includes a step of fixing the optical layer laminate, the phosphor layer and the wavelength selective reflection layer integrally, and then fixing the optical layer laminate, the phosphor layer and the wavelength selective reflection layer to the rear surface of the liquid crystal display panel.
　ある実施形態において、前記工程Ｂは、前記蛍光体層と前記波長選択反射層とを一体に固定した後、前記光学層積層体と一体化する工程を包含する。 In one embodiment, the step B includes a step of integrally fixing the phosphor layer and the wavelength selective reflection layer, and then integrating the phosphor layer and the optical layer laminate.
　ある実施形態において、前記工程Ｂは、前記光学層積層体と前記蛍光体層とを一体に固定した後、前記波長選択反射層と一体化する工程を包含する。 In one embodiment, the step B includes a step of integrally fixing the optical layer laminate and the phosphor layer and then integrating the optical layer laminate with the wavelength selective reflection layer.
　ある実施形態において、前記光学層積層体と前記蛍光体層とを互いに接着する工程は、ベースフィルムと前記ベースフィルムの両側に形成された２つの接着層とを有する両面接着フィルムを用いて行われ、前記２つの接着層のうちの前記光学層積層体に近い方の接着層は、離散的に配置された複数の接着部を有する。 In one embodiment, the step of bonding the optical layer laminate and the phosphor layer to each other is performed using a double-sided adhesive film having a base film and two adhesive layers formed on both sides of the base film. The adhesive layer closer to the optical layer laminate among the two adhesive layers has a plurality of discretely arranged adhesive portions.
　ある実施形態において、前記光学層積層体と前記蛍光体層とを互いに接着する工程は、離散的に配置された複数の接着部を有する接着層の両側ｓｓに、前記光学層積層体および前記蛍光体層を接触させる工程を包含する。 In one embodiment, the step of adhering the optical layer laminate and the phosphor layer to each other includes disposing the optical layer laminate and the phosphor on both sides ss of an adhesive layer having a plurality of discretely arranged adhesive portions. Contacting the body layer.
　ある実施形態において、前記光学層積層体と前記蛍光体層とを互いに接着する工程は、前記光学層積層体の一面に接着層を付与した後、前記蛍光体層と一体化する工程を包含する、または、前記蛍光体層の一面に接着層を付与した後、前記光学層積層体と一体化する工程を包含する。 In one embodiment, the step of bonding the optical layer laminate and the phosphor layer to each other includes a step of applying an adhesive layer to one surface of the optical layer laminate and then integrating the phosphor layer with the phosphor layer. Alternatively, the method further includes a step of providing an adhesive layer on one surface of the phosphor layer and then integrating the phosphor layer with the optical layer laminate.
　本発明の実施形態によると、リモートフォスファー方式のバックライト装置を備えた液晶表示装置の薄型化を含む性能を向上させる、および／または量産性を向上させることができる。 According to the embodiment of the present invention, it is possible to improve the performance of the liquid crystal display device including the backlight device of the remote phosphor system, including the thickness reduction, and / or the mass productivity.
本発明の実施形態による液晶表示装置１００を模式的に示す断面図である。FIG. 1 is a cross-sectional view schematically illustrating a liquid crystal display device 100 according to an embodiment of the present invention. 本発明の他の実施形態による液晶表示装置１００Ｒを模式的に示す断面図である。FIG. 10 is a cross-sectional view schematically illustrating a liquid crystal display device 100R according to another embodiment of the present invention. 液晶表示装置１００の模式的な断面図であり、図１の一部を拡大して示す図である。FIG. 2 is a schematic cross-sectional view of the liquid crystal display device 100, and is an enlarged view of a part of FIG. 液晶表示装置１００Ｒの模式的な断面図であり、図２の一部を拡大して示す図である。FIG. 3 is a schematic cross-sectional view of the liquid crystal display device 100R, and is a diagram showing a part of FIG. 2 in an enlarged manner. 本発明のさらに他の実施形態による液晶表示装置１００Ｂを模式的に示す断面図である。FIG. 11 is a cross-sectional view schematically illustrating a liquid crystal display device 100B according to still another embodiment of the present invention. 液晶表示装置１００Ｂの模式的な断面図であり、図５の一部を拡大して示す図である。FIG. 6 is a schematic cross-sectional view of the liquid crystal display device 100B, and is an enlarged view showing a part of FIG. 実験例の評価結果を示すグラフである。9 is a graph showing evaluation results of an experimental example. （ａ）は、比較例１のバックライト装置９５０を模式的に示す断面図であり、（ｂ）は、バックライト装置９５０を有する比較例１の液晶表示装置９００を模式的に示す断面図である。(A) is a sectional view schematically showing a backlight device 950 of Comparative Example 1, and (b) is a sectional view schematically showing a liquid crystal display device 900 of Comparative Example 1 having the backlight device 950. is there. （ａ）は、比較例２のバックライト装置９５０Ｒを用いて部分駆動を行うときの模式的な図であり、（ｂ）は、バックライト装置９５０Ｒを有する比較例２の液晶表示装置９００Ｒに表示される画像パターンを模式的に示す図である。(A) is a schematic diagram when partial driving is performed using the backlight device 950R of Comparative Example 2, and (b) is displayed on the liquid crystal display device 900R of Comparative Example 2 having the backlight device 950R. FIG. 4 is a diagram schematically showing an image pattern to be performed. （ａ）は、バックライト装置９５０Ｒを用いて部分駆動を行わないときの模式的な図であり、（ｂ）は、液晶表示装置９００Ｒに表示される画像パターンを模式的に示す図である。(A) is a schematic diagram when partial driving is not performed using the backlight device 950R, and (b) is a diagram schematically illustrating an image pattern displayed on the liquid crystal display device 900R. 他の比較例の液晶表示装置９００Ｂを模式的に示す断面図である。It is sectional drawing which shows typically the liquid crystal display device 900B of another comparative example.
　まず、図８および図９を参照して、公知のリモートフォスファー方式のバックライト装置の構造および改善すべき点を説明する。ここで例示する比較例１のバックライト装置９５０は、例えば、特許文献１に記載されているバックライト装置と同様の構造を有している。 First, referring to FIGS. 8 and 9, the structure of a known remote phosphor type backlight device and points to be improved will be described. The backlight device 950 of Comparative Example 1 illustrated here has, for example, the same structure as the backlight device described in Patent Document 1.
　図８（ａ）は、バックライト装置９５０を模式的に示す断面図であり、図８（ｂ）は、バックライト装置９５０を有する比較例１の液晶表示装置９００を模式的に示す断面図である。 FIG. 8A is a cross-sectional view schematically illustrating a backlight device 950, and FIG. 8B is a cross-sectional view schematically illustrating a liquid crystal display device 900 of Comparative Example 1 including the backlight device 950. is there.
　図８（ａ）に示すように、バックライト装置９５０は、ＬＥＤ基板９０１と、ＬＥＤ基板９０１に支持された複数の発光素子９１０と、複数の発光素子９１０から離れて配置された蛍光体シート９２０と、蛍光体シート９２０と複数の発光素子９１０との間に配置された波長選択性反射膜（ダイクロイック・フィルタ）９３０とを有する。蛍光体シート９２０は、発光素子９１０から出射された光によって励起され、蛍光を発する。発光素子９１０は例えば青色ＬＥＤであり、蛍光体シート９２０は緑色蛍光を発する蛍光体および赤色蛍光を発する蛍光体を含む。リモートフォスファー方式では、蛍光体シート９２０が発光素子９１０から離れて配置されるので、発光素子９１０が発する熱に起因する蛍光体の劣化を抑制することができる。 As shown in FIG. 8A, the backlight device 950 includes an LED substrate 901, a plurality of light emitting elements 910 supported by the LED substrate 901, and a phosphor sheet 920 disposed apart from the plurality of light emitting elements 910. And a wavelength-selective reflective film (dichroic filter) 930 disposed between the phosphor sheet 920 and the plurality of light emitting elements 910. The phosphor sheet 920 emits fluorescence when excited by the light emitted from the light emitting element 910. The light emitting element 910 is, for example, a blue LED, and the phosphor sheet 920 includes a phosphor that emits green fluorescence and a phosphor that emits red fluorescence. In the remote phosphor method, since the phosphor sheet 920 is disposed apart from the light emitting element 910, deterioration of the phosphor due to heat generated by the light emitting element 910 can be suppressed.
　蛍光体シート９２０は、例えば、蛍光体層９２１と、蛍光体層９２１の両側に設けられた保護層９２２および９２３とを有する。 The phosphor sheet 920 has, for example, a phosphor layer 921 and protective layers 922 and 923 provided on both sides of the phosphor layer 921.
　波長選択性反射膜９３０は、発光素子９１０から出射された光の波長領域の少なくとも一部を透過し、蛍光体シート９２０から発せられた光（「蛍光」）の少なくとも一部を反射する。好ましくは、波長選択性反射膜９３０は、発光素子９１０から出射された光の全てを透過し、蛍光体シート９２０から発せられた光の全てを反射する。例えば発光素子９１０が青色ＬＥＤである場合、波長選択性反射膜９３０は、青色ＬＥＤの発光波長領域（すなわち青色）の光を透過し、緑色から赤色にかけての波長領域の光を反射する。図９を参照して以下で説明するように、バックライト装置９５０は、波長選択性反射膜９３０を有することによって、部分駆動を行うときの色むらを抑制することができる。なお、本明細書において、蛍光体シートが発する光を「蛍光」ということがある。特に断らない限り、「蛍光」は、狭義の蛍光およびりん光を含む。 The wavelength-selective reflection film 930 transmits at least a part of the wavelength region of the light emitted from the light emitting element 910 and reflects at least a part of the light (“fluorescence”) emitted from the phosphor sheet 920. Preferably, the wavelength-selective reflective film 930 transmits all of the light emitted from the light emitting element 910 and reflects all of the light emitted from the phosphor sheet 920. For example, when the light emitting element 910 is a blue LED, the wavelength-selective reflection film 930 transmits light in the emission wavelength region of the blue LED (that is, blue) and reflects light in the wavelength region from green to red. As described below with reference to FIG. 9, the backlight device 950 includes the wavelength-selective reflective film 930, and thus can suppress color unevenness when performing partial driving. In this specification, the light emitted from the phosphor sheet may be referred to as “fluorescence”. Unless otherwise specified, “fluorescence” includes fluorescence and phosphorescence in a narrow sense.
　バックライト装置９５０は、複数の発光素子９１０と波長選択性反射膜９３０との間に拡散板９４０をさらに有している。拡散板９４０は、複数の発光素子９１０から出射され、波長選択性反射膜９３０に至る光の強度分布の均一性を高めるように作用する。複数の発光素子９１０のピッチＰに対する、ＬＥＤ基板９０１と拡散板９４０との間の距離Ｄ１の比（Ｄ１／Ｐ）を大きくすることによって、強度分布の均一性を高めることができるが、バックライト装置が厚くなるという問題がある。拡散板９４０を省略する場合は、ＬＥＤ基板９０１と波長選択性反射膜９３０との間の距離を大きくすればよいが、バックライト装置はさらに厚くなる。ＬＥＤチップを封止するガラス等のレンズ機能を利用して、ＬＥＤチップから出射される光の配光分布を調整することによっても、強度分布の均一性を高めることはできるが、バックライト装置が厚くなる、および／またはＬＥＤの配列密度を高めることができないという問題がある。 The backlight device 950 further includes a diffusion plate 940 between the plurality of light emitting elements 910 and the wavelength selective reflection film 930. The diffusion plate 940 acts to increase the uniformity of the intensity distribution of light emitted from the plurality of light emitting elements 910 and reaching the wavelength-selective reflection film 930. By increasing the ratio (D1 / P) of the distance D1 between the LED substrate 901 and the diffusion plate 940 to the pitch P of the plurality of light emitting elements 910, the uniformity of the intensity distribution can be improved. There is a problem that the device becomes thick. When the diffusion plate 940 is omitted, the distance between the LED substrate 901 and the wavelength-selective reflection film 930 may be increased, but the backlight device is further thickened. By adjusting the light distribution of the light emitted from the LED chip by using a lens function of glass or the like for sealing the LED chip, the uniformity of the intensity distribution can be improved. There is a problem in that the thickness is increased and / or the array density of the LEDs cannot be increased.
　さらに、そもそも従来は、特許文献１に記載の様に、蛍光体シート９２０、波長選択性反射膜９３０等を含むバックライト装置９５０を用意し、バックライト装置９５０と液晶表示パネルとを組み合わせることによって、液晶表示装置を作製していた。したがって、図８（ｂ）にバックライト装置９５０を有する比較例１の液晶表示装置９００の断面図を模式的に示すように、液晶表示パネル９９０と、バックライト装置９５０との間には、例えば１ｍｍ～２ｍｍ程度の空隙Ｇが設けられていた。これはバックライト装置９５０の液晶表示パネル９９０側に配置される光学シートと、液晶表示パネル９９０のバックライト装置９５０側の光学シートとが、摩擦等によって傷つくことを防止するためである。 Further, conventionally, as described in Patent Document 1, a backlight device 950 including a phosphor sheet 920, a wavelength-selective reflective film 930, and the like is prepared, and the backlight device 950 and a liquid crystal display panel are combined. And a liquid crystal display device. Therefore, as schematically shown in a cross-sectional view of the liquid crystal display device 900 of Comparative Example 1 having the backlight device 950 in FIG. 8B, for example, a portion between the liquid crystal display panel 990 and the backlight device 950 is provided. A gap G of about 1 mm to 2 mm was provided. This is to prevent the optical sheet disposed on the liquid crystal display panel 990 side of the backlight device 950 and the optical sheet on the backlight device 950 side of the liquid crystal display panel 990 from being damaged by friction or the like.
　次に、図９を参照して、波長選択性反射膜９３０の作用・効果を説明する。 Next, the operation and effect of the wavelength-selective reflection film 930 will be described with reference to FIG.
　図９（ａ）は、比較例２のバックライト装置９５０Ｒを模式的に示す断面図である。バックライト装置９５０Ｒは、波長選択性反射膜を有しないリモートフォスファー方式の直下型バックライト装置である。バックライト装置９５０Ｒは、波長選択性反射膜９３０を有しない点において、比較例１のバックライト装置９５０と異なる。図９（ａ）に示すように、バックライト装置９５０Ｒを用いて部分駆動を行うと、色むらが生じることがある。バックライト装置９５０Ｒは、部分駆動を行っているとき、発光素子９１０が点灯している点灯領域Ｒｏｎと、発光素子９１０が点灯していない消灯領域Ｒｏｆｆとを有する。図９（ｂ）に、バックライト装置９５０Ｒを有する比較例２の液晶表示装置９００Ｒに表示される画像パターンを模式的に示す。図９（ｂ）は、液晶表示装置９００Ｒが有する液晶表示パネルの法線方向から見たときの模式的な図である。 FIG. 9A is a cross-sectional view schematically showing a backlight device 950R of Comparative Example 2. The backlight device 950R is a direct-type backlight device of a remote phosphor type having no wavelength selective reflection film. The backlight device 950R is different from the backlight device 950 of Comparative Example 1 in that the backlight device 950R does not include the wavelength-selective reflection film 930. As shown in FIG. 9A, when partial driving is performed using the backlight device 950R, color unevenness may occur. The backlight device 950R has a lighting area Ron in which the light emitting element 910 is lit and a light extinguishing area Roff in which the light emitting element 910 is not lit when performing partial driving. FIG. 9B schematically shows an image pattern displayed on the liquid crystal display device 900R of Comparative Example 2 having the backlight device 950R. FIG. 9B is a schematic diagram when the liquid crystal display panel of the liquid crystal display device 900R is viewed from the normal direction.
　図９（ｂ）に示すように、点灯領域Ｒｏｎの周辺領域の暗部となるべき部分の一部（図中の左下がりハッチング部）において、黄色味が強くなってしまう（「色つき」ということもある。）ことがある。この現象の原因の１つとして、点灯領域Ｒｏｎの蛍光体シート９２０から発せられた光のうち後方（ＬＥＤ基板９０１側）に出射された光Ｌ2が、ＬＥＤ基板９０１で反射されることによって消灯領域Ｒｏｆｆに入射することが考えられる。光Ｌ2は、青色光よりも赤色から緑色にかけての波長領域の光を多く含む。 As shown in FIG. 9B, in a part (a hatched portion on the lower left in the figure) of a portion to be a dark portion in a peripheral region of the lighting region Ron, yellowish color becomes strong (referred to as “colored”). There is also.) One cause of this phenomenon, extinguished by the light L 2 emitted backward (LED substrate 901 side) of the emitted from the phosphor sheet 920 of the lighting region Ron light is reflected by the LED substrates 901 It is conceivable that the light enters the region Roff. Light L 2 comprises more light in the wavelength region of toward green from red than blue light.
　なお、ＬＥＤ基板９０１の表面（複数の発光素子９１０を有する面）は、輝度を高めるために、発光素子９１０の間に反射シートを有することがある。反射シートを設けないと、十分な輝度が得られないこともあった。反射シートを設けると、色むらの発生がさらに顕著になり得る。 Note that the surface of the LED substrate 901 (the surface having the plurality of light-emitting elements 910) may have a reflection sheet between the light-emitting elements 910 in order to increase luminance. Without the reflective sheet, sufficient luminance may not be obtained in some cases. When the reflection sheet is provided, the occurrence of color unevenness may be more remarkable.
　これに対して、図８（ａ）に示した比較例１のバックライト装置９５０は、波長選択性反射膜９３０を有するので、蛍光体シート９２０から後方（ＬＥＤ基板９０１側）に発せられ、ＬＥＤ基板９０１で反射された光が、消灯領域の蛍光体シート９２０に入射することを抑制することができる。これにより、部分駆動を行うときの色むらを抑制することができる。 On the other hand, since the backlight device 950 of Comparative Example 1 shown in FIG. 8A has the wavelength-selective reflection film 930, the backlight device 950 is emitted backward from the phosphor sheet 920 (to the LED substrate 901 side), Light reflected by the substrate 901 can be suppressed from entering the phosphor sheet 920 in the light-off region. Thereby, it is possible to suppress color unevenness when performing partial driving.
　上述したように、特許文献１には、部分駆動を行うリモートフォスファー方式の直下型のバックライト装置が開示されている。しかしながら、薄型化に限界があるという問題は、部分駆動の有無に限られず、リモートフォスファー方式のバックライト装置を備える液晶表示装置に共通の問題である。本発明の実施形態は、部分駆動の有無に限られず、リモートフォスファー方式のバックライト装置を備える液晶表示装置に適用され得る。本発明の実施形態による液晶表示装置が備えるバックライト装置は、例えば直下型である。エッジライト型であってもよい。 As described above, Patent Literature 1 discloses a direct-type backlight device of a remote phosphor type that performs partial driving. However, the problem that there is a limit to the reduction in thickness is not limited to the presence or absence of partial driving, and is a problem common to liquid crystal display devices including a remote phosphor type backlight device. Embodiments of the present invention are not limited to the presence or absence of partial driving, and can be applied to a liquid crystal display device including a remote phosphor type backlight device. The backlight device included in the liquid crystal display device according to the embodiment of the present invention is, for example, a direct type. An edge light type may be used.
　以下、本発明の実施形態による液晶表示装置およびその製造方法を説明する。なお、本発明の実施形態は、以下に例示する実施形態に限定されない。以下の説明において、同様の機能を有する構成要素には共通の参照符号を付し、説明の重複を避ける場合がある。 Hereinafter, a liquid crystal display device according to an embodiment of the present invention and a method for manufacturing the same will be described. Note that embodiments of the present invention are not limited to the embodiments exemplified below. In the following description, components having the same functions will be denoted by the same reference numerals, and overlapping description may be avoided.
　図１を参照しながら、本発明の実施形態による液晶表示装置１００を説明する。図１は、本発明の実施形態による液晶表示装置１００を模式的に示す断面図である。 A liquid crystal display device 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view schematically showing a liquid crystal display device 100 according to an embodiment of the present invention.
　図１に示すように、液晶表示装置１００は、液晶表示パネル１０と、液晶表示パネル１０の背面１０ｒに向けて光を出射するバックライト装置５０とを備える。バックライト装置５０は、液晶表示パネル１０の背面１０ｒに向けて励起光を出射するように複数のＬＥＤチップ２２が表面２１ｓに配列されたＬＥＤ基板２１と、励起光を受けて、蛍光を発する蛍光体を含む蛍光体層２５と、蛍光体層２５とＬＥＤ基板２１との間に配置され、励起光の透過率が蛍光の透過率よりも高い波長選択反射層２８と、蛍光体層２５の液晶表示パネル１０側に配置された光学層積層体３０とを有する。光学層積層体３０、蛍光体層２５および波長選択反射層２８は、液晶表示パネル１０の背面１０ｒに、複数の接着層４０ａ、４０ｂおよび４０ｃを介して一体に固定されている。 As shown in FIG. 1, the liquid crystal display device 100 includes a liquid crystal display panel 10 and a backlight device 50 that emits light toward the back surface 10r of the liquid crystal display panel 10. The backlight device 50 includes an LED substrate 21 on which a plurality of LED chips 22 are arranged on a front surface 21s so as to emit excitation light toward the back surface 10r of the liquid crystal display panel 10, and a fluorescent light that emits fluorescent light when receiving the excitation light. A phosphor layer 25 including a body, a wavelength selective reflection layer 28 disposed between the phosphor layer 25 and the LED substrate 21 and having a transmittance of excitation light higher than a transmittance of fluorescence, and a liquid crystal of the phosphor layer 25. And an optical layer laminate 30 arranged on the display panel 10 side. The optical layer laminate 30, the phosphor layer 25, and the wavelength selective reflection layer 28 are integrally fixed to the back surface 10r of the liquid crystal display panel 10 via a plurality of adhesive layers 40a, 40b, and 40c.
　液晶表示装置１００において、光学層積層体３０、蛍光体層２５および波長選択反射層２８は、液晶表示パネル１０の背面１０ｒに、複数の接着層４０ａ、４０ｂおよび４０ｃを介して一体に固定されている。言い換えると、光学層積層体３０、蛍光体層２５および波長選択反射層２８は液晶表示パネル１０に支持されている。このように、液晶表示装置１００においては、バックライト装置５０の液晶表示パネル１０側に配置される光学シートと、液晶表示パネル１０との間に空隙が形成されないので、その分、従来の液晶表示装置よりも薄くできる。さらに、液晶表示装置１００は、光拡散層（例えば光拡散板）をＬＥＤ基板２１と波長選択反射層２８との間に有しないので、さらに薄型化することができる。 In the liquid crystal display device 100, the optical layer laminate 30, the phosphor layer 25, and the wavelength selective reflection layer 28 are integrally fixed to the back surface 10r of the liquid crystal display panel 10 via a plurality of adhesive layers 40a, 40b, and 40c. I have. In other words, the optical layer stack 30, the phosphor layer 25, and the wavelength selective reflection layer 28 are supported by the liquid crystal display panel 10. As described above, in the liquid crystal display device 100, no gap is formed between the liquid crystal display panel 10 and the optical sheet disposed on the liquid crystal display panel 10 side of the backlight device 50. It can be thinner than the device. Further, since the liquid crystal display device 100 does not include a light diffusion layer (for example, a light diffusion plate) between the LED substrate 21 and the wavelength selective reflection layer 28, the thickness can be further reduced.
　光学層積層体３０は、蛍光体層２５から発せられた蛍光を液晶表示パネル１０に効果的に照射するために、あるいは、蛍光体層２５を保護するために、設けられている。光学層積層体３０は、少なくとも１つの光学層を含む。光学層は保護層であってもよいし、接着層であってもよい。光学層積層体は、以下で例示するような機能的な光学層を含むことが好ましい。ただし、光学層積層体の構成は例示するものに限られない。 (4) The optical layer laminate 30 is provided to effectively irradiate the fluorescent light emitted from the phosphor layer 25 to the liquid crystal display panel 10 or to protect the phosphor layer 25. The optical layer stack 30 includes at least one optical layer. The optical layer may be a protective layer or an adhesive layer. The optical layer laminate preferably includes a functional optical layer as exemplified below. However, the configuration of the optical layer laminate is not limited to the illustrated one.
　この例では、光学層積層体３０は、２枚のプリズムシート３４ａおよび３４ｂと、これらの上に配置された偏光選択反射層３２とを含む。２枚のプリズムシート３４ａおよび３４ｂは、それぞれのプリズムの稜線が互いに略直交する様に配置されている。プリズムシート３４ａおよび３４ｂは、それぞれ、例えば、ベースフィルム３４ｂａまたは３４ｂｂと、ベースフィルム３４ｂａまたは３４ｂｂ上に形成されたプリズム層３４ｐａまたは３４ｐｂとを有する。プリズムシート３４ａ、３４ｂとしては、例えば３Ｍ社製のＢＥＦを用いることができる。偏光選択反射層３２は、例えば、屈折率の異なる膜を積層した積層構造を有する光学多層膜である。偏光選択反射層３２としては、例えば、３Ｍ社製のＤＢＥＦ（登録商標）を用いることができる。例えば、２枚のプリズムシート３４ａおよび３４ｂのうち、蛍光体層２５に近い方のプリズムシート３４ｂの、ＬＥＤ基板２１を向く表面は鏡面である。 In this example, the optical layer laminate 30 includes two prism sheets 34a and 34b, and a polarization selective reflection layer 32 disposed thereon. The two prism sheets 34a and 34b are arranged such that the ridges of the respective prisms are substantially orthogonal to each other. Each of the prism sheets 34a and 34b has, for example, a base film 34ba or 34bb, and a prism layer 34pa or 34pb formed on the base film 34ba or 34bb, respectively. As the prism sheets 34a and 34b, for example, BEF manufactured by 3M can be used. The polarization selective reflection layer 32 is, for example, an optical multilayer film having a laminated structure in which films having different refractive indexes are laminated. As the polarization selective reflection layer 32, for example, DBEF (registered trademark) manufactured by 3M can be used. For example, of the two prism sheets 34a and 34b, the surface facing the LED substrate 21 of the prism sheet 34b closer to the phosphor layer 25 is a mirror surface.
　複数の接着層４０ａ、４０ｂおよび４０ｃは、光学層積層体３０と蛍光体層２５との間に形成された第１接着層４０ａを含む。第１接着層４０ａは、離散的に配置された複数の接着部４０ｐを有し、かつ、光学層積層体３０と蛍光体層２５との間に空気層を形成している。 The plurality of adhesive layers 40a, 40b and 40c include the first adhesive layer 40a formed between the optical layer laminate 30 and the phosphor layer 25. The first adhesive layer 40a has a plurality of discretely arranged adhesive portions 40p, and forms an air layer between the optical layer laminate 30 and the phosphor layer 25.
　実験例を後に示すように、蛍光体層２５の液晶表示パネル１０側に設けられた第１接着層４０ａの構造によって、輝度を向上させることができることが分かった。すなわち、第１接着層４０ａが離散的に配置された複数の接着部４０ｐを有し、かつ、光学層積層体３０と蛍光体層２５との間に空気層を形成していることによって、（例えば図２に示す液晶表示装置１００Ｒに比べて）輝度を向上させることができることが分かった。 (4) As will be described later in an experimental example, it was found that the luminance can be improved by the structure of the first adhesive layer 40a provided on the liquid crystal display panel 10 side of the phosphor layer 25. That is, since the first adhesive layer 40a has a plurality of adhesive portions 40p arranged discretely and forms an air layer between the optical layer laminate 30 and the phosphor layer 25, For example, it was found that the luminance can be improved (compared to the liquid crystal display device 100R shown in FIG. 2).
　第１接着層４０ａは、例えば、ベースフィルム（例えばＰＥＴフィルム）と、ベースフィルムの両側に形成された２つの接着層とを含む両面接着フィルムに含まれる。この場合、２つの接着層のうちの第１接着層４０ａが、光学層積層体３０の最も近くに配置されるようにすると、逆の配置に比べて、輝度をより向上させることができる。このとき、２つの接着層のうちの他方の接着層は、ベースフィルムの全面に連続的に形成された接着層であってもよい。 The first adhesive layer 40a is included in, for example, a double-sided adhesive film including a base film (for example, a PET film) and two adhesive layers formed on both sides of the base film. In this case, when the first adhesive layer 40a of the two adhesive layers is arranged closest to the optical layer laminate 30, the luminance can be further improved as compared with the opposite arrangement. At this time, the other of the two adhesive layers may be an adhesive layer continuously formed on the entire surface of the base film.
　蛍光体層２５の両側に、オプショナルな保護層２６ａおよび２６ｂが設けられていてもよい。波長選択反射層２８と、蛍光体層２５（または蛍光体層２５のＬＥＤ基板２１側に設けられた保護層２６ｂ）とは、例えば、第２接着層４０ｂを介して互いに貼り合せられている。 保護 Optional protective layers 26a and 26b may be provided on both sides of the phosphor layer 25. The wavelength selective reflection layer 28 and the phosphor layer 25 (or the protection layer 26b provided on the LED substrate 21 side of the phosphor layer 25) are bonded to each other via, for example, a second adhesive layer 40b.
　液晶表示パネル１０は、液晶セル１と、液晶セル１の両側に設けられた偏光板１１ａおよび１１ｂとを有する。偏光板１１ａおよび１１ｂは、例えば、それぞれ接着層４０ｄおよび４０ｅを介して、液晶セル１に貼り合せられている。液晶表示装置１００が有する液晶表示パネルは図示する例に限られず、公知の液晶表示パネルであってよい。 The liquid crystal display panel 10 includes the liquid crystal cell 1 and polarizing plates 11a and 11b provided on both sides of the liquid crystal cell 1. The polarizing plates 11a and 11b are attached to the liquid crystal cell 1 via, for example, adhesive layers 40d and 40e, respectively. The liquid crystal display panel included in the liquid crystal display device 100 is not limited to the illustrated example, and may be a known liquid crystal display panel.
　図２に、本発明の実施形態の他の例を示す。図２は、液晶表示装置１００Ｒを模式的に示す断面図である。 FIG. 2 shows another example of the embodiment of the present invention. FIG. 2 is a cross-sectional view schematically illustrating the liquid crystal display device 100R.
　図２に示すように、液晶表示装置１００Ｒは、液晶表示パネル１０の法線方向から見たとき、第１接着層４０Ｒが蛍光体層２５のほぼ全面と重なるように形成されている点において、図１に示した液晶表示装置１００と異なる。すなわち、液晶表示装置１００Ｒの第１接着層４０Ｒは、離散的に配置された複数の接着部を含まず、光学層積層体３０と蛍光体層２５との間に空気層を形成していない。 As shown in FIG. 2, the liquid crystal display device 100R is configured such that the first adhesive layer 40R is formed so as to overlap substantially the entire surface of the phosphor layer 25 when viewed from the normal direction of the liquid crystal display panel 10. This is different from the liquid crystal display device 100 shown in FIG. That is, the first adhesive layer 40R of the liquid crystal display device 100R does not include a plurality of discretely arranged adhesive portions, and does not form an air layer between the optical layer laminate 30 and the phosphor layer 25.
　液晶表示装置１００Ｒは、図１に示した液晶表示装置１００と同様に、バックライト装置５０の液晶表示パネル１０側に配置される光学シートと、液晶表示パネル１０との間に空隙が形成されないので、従来の液晶表示装置よりも薄くできる。さらに、液晶表示装置１００Ｒは、光拡散層をＬＥＤ基板２１と波長選択反射層２８との間に有しないので、さらに薄型化することができる。 In the liquid crystal display device 100R, similarly to the liquid crystal display device 100 shown in FIG. 1, no gap is formed between the optical sheet disposed on the liquid crystal display panel 10 side of the backlight device 50 and the liquid crystal display panel 10. , And can be thinner than a conventional liquid crystal display device. Further, since the liquid crystal display device 100R does not have the light diffusion layer between the LED substrate 21 and the wavelength selective reflection layer 28, the thickness can be further reduced.
　図１に示した液晶表示装置１００は、液晶表示装置１００Ｒに比べて、輝度を向上させることができる。これについて、図３および図４を参照して説明する。なお、以下は本発明者の考察であり、本発明を限定するものではない。 輝 度 The liquid crystal display device 100 shown in FIG. 1 can improve the luminance as compared with the liquid crystal display device 100R. This will be described with reference to FIGS. The following is a consideration of the present inventors and does not limit the present invention.
　図３および図４は、それぞれ、液晶表示装置１００および液晶表示装置１００Ｒの模式的な断面図である。図３および図４は、それぞれ、図１および図２の一部を拡大して模式的に示している。 FIGS. 3 and 4 are schematic sectional views of the liquid crystal display device 100 and the liquid crystal display device 100R, respectively. 3 and 4 schematically show a part of FIGS. 1 and 2 in an enlarged manner, respectively.
　図３に示すように、液晶表示装置１００において、ＬＥＤチップ２２から液晶表示パネル１０の背面１０ｒに向けて出射された励起光Ｌａは、蛍光体層２５に入射する。蛍光体層２５は、励起光Ｌａを受けて、蛍光Ｌｂを発する蛍光体２５ｑを含む。蛍光Ｌｂは、狭義の蛍光およびりん光を含む。ここでは、蛍光体層２５は、樹脂中に分散された量子ドット蛍光体２５ｑを含む。励起光Ｌａが量子ドット蛍光体２５ｑに入射すると、蛍光Ｌｂが発せられる。励起光Ｌａの一部は、蛍光体層２５を通過し液晶表示パネル１０に向かって発せられる。励起光Ｌａの一部は、保護層２６ａと第１接着層４０ａが形成する空気層との界面で反射されることによって、再び蛍光体層２５に入射する。これにより、励起光の利用効率を向上させることができる。励起光Ｌａは、第１接着層４０ａが形成する空気層とプリズムシート３４ｂとの間の界面でも反射され、再び蛍光体層２５に入射する。液晶表示装置１００においては、励起光の利用効率が高いので、液晶表示装置１００Ｒに比べて輝度を向上させることができる。 As shown in FIG. 3, in the liquid crystal display device 100, the excitation light La emitted from the LED chip 22 toward the rear surface 10r of the liquid crystal display panel 10 enters the phosphor layer 25. The phosphor layer 25 includes a phosphor 25q that receives the excitation light La and emits the fluorescence Lb. The fluorescence Lb includes fluorescence and phosphorescence in a narrow sense. Here, the phosphor layer 25 includes a quantum dot phosphor 25q dispersed in a resin. When the excitation light La enters the quantum dot phosphor 25q, the fluorescence Lb is emitted. Part of the excitation light La passes through the phosphor layer 25 and is emitted toward the liquid crystal display panel 10. A part of the excitation light La is reflected on the interface between the protective layer 26a and the air layer formed by the first adhesive layer 40a, and then enters the phosphor layer 25 again. Thereby, the utilization efficiency of the excitation light can be improved. The excitation light La is also reflected at the interface between the air layer formed by the first adhesive layer 40a and the prism sheet 34b, and reenters the phosphor layer 25. In the liquid crystal display device 100, since the utilization efficiency of the excitation light is high, the luminance can be improved as compared with the liquid crystal display device 100R.
　これに対して、図４に示すように、液晶表示装置１００Ｒにおいては、保護層２６ａと第１接着層４０Ｒとの界面における励起光Ｌａの反射が抑制される。保護層２６ａの屈折率と第１接着層４０Ｒの屈折率との差は、保護層２６ａの屈折率ａと空気層の屈折率との差よりも小さいためである。同様に、第１接着層４０Ｒとプリズムシート３４ｂとの界面においても励起光Ｌａの反射が抑制される。第１接着層４０Ｒの屈折率とプリズムシート３４ｂの屈折率（プリズムシート３４ｂのベースフィルム３４ｂｂの屈折率）との差は、空気層の屈折率とプリズムシート３４ｂの屈折率（プリズムシート３４ｂのベースフィルム３４ｂｂの屈折率）との差よりも小さいためである。従って、励起光の利用効率は、液晶表示装置１００に比べて低い。極端な例を考えると、保護層２６ａ、第１接着層４０Ｒおよびプリズムシート３４ｂのベースフィルム３４ｂｂの屈折率がほぼ等しい場合、蛍光体層２５から発せられる励起光Ｌａはこれらの層の間の界面で反射されずにプリズムシート３４ｂに入射することになる。 4 On the other hand, as shown in FIG. 4, in the liquid crystal display device 100R, the reflection of the excitation light La at the interface between the protective layer 26a and the first adhesive layer 40R is suppressed. This is because the difference between the refractive index of the protective layer 26a and the refractive index of the first adhesive layer 40R is smaller than the difference between the refractive index a of the protective layer 26a and the refractive index of the air layer. Similarly, the reflection of the excitation light La is suppressed at the interface between the first adhesive layer 40R and the prism sheet 34b. The difference between the refractive index of the first adhesive layer 40R and the refractive index of the prism sheet 34b (the refractive index of the base film 34bb of the prism sheet 34b) is determined by the refractive index of the air layer and the refractive index of the prism sheet 34b (the base of the prism sheet 34b). This is because it is smaller than the difference from the refractive index of the film 34bb). Therefore, the utilization efficiency of the excitation light is lower than that of the liquid crystal display device 100. Considering an extreme example, when the refractive indices of the protective layer 26a, the first adhesive layer 40R, and the base film 34bb of the prism sheet 34b are substantially equal, the excitation light La emitted from the phosphor layer 25 causes an interface between these layers. And is incident on the prism sheet 34b without being reflected.
　第１接着層４０ａにおける複数の接着部４０ｐの占有面積率は、励起光の利用効率を向上させる観点からは、小さいことが好ましく、例えば５０％以下である。バックライト装置５０の機械強度を考慮すると、大きいことが好ましく、例えば５０％以上であることが好ましい。個々の接着部４０ｐのサイズ（面積円相当径をいい、例えば接着部４０ｐが略円形である場合は直径（ドット径）である。）は、例えば３００μｍ～６００μｍ程度である。これより小さいと、いくつかの接着部４０ｐが欠落するおそれがある。なお、画素配列の周期構造と干渉しないように、接着部４０ｐのサイズ、ピッチおよび配列方向を調整することが好ましい。第１接着層４０ａは、例えば、光学的に透明であり散乱しない接着剤（optical clear adhesive）を用いて形成される。 The occupied area ratio of the plurality of bonding portions 40p in the first bonding layer 40a is preferably small, for example, 50% or less from the viewpoint of improving the utilization efficiency of the excitation light. Considering the mechanical strength of the backlight device 50, it is preferably large, for example, 50% or more. The size of each of the bonded portions 40p (refers to the area circle equivalent diameter, for example, the diameter (dot diameter) when the bonded portion 40p is substantially circular) is, for example, about 300 μm to 600 μm. If it is smaller than this, there is a possibility that some of the bonding portions 40p may be missing. It is preferable to adjust the size, pitch, and arrangement direction of the bonding portion 40p so as not to interfere with the periodic structure of the pixel array. The first adhesive layer 40a is formed, for example, using an optically clear adhesive that is optically transparent and does not scatter.
　このように、蛍光体層２５（または蛍光体層２５の液晶表示パネル１０側に設けられた保護層２６ａ）と光学層積層体３０との間に空気層が形成されていると、励起光の利用効率を向上させることができ、これにより液晶表示装置の輝度を向上させることができると考えられる。光学層積層体３０の構造は、例示したものに限られない。光学層積層体を構成する光学層のうち、最も蛍光体層２５に近い層は、プリズムシートであってもよいし、偏光選択反射層、偏光層、光拡散層、透明シート、保護層等、任意の層であり得る。励起光の利用効率を向上させる観点からは、蛍光体層２５を通過して液晶表示パネル１０に向けて発せられた励起光が、再び蛍光体層２５に入射する割合が向上されればよい。従って、図１に示した空気層を形成する第１接着層４０ａに限られず、例えば、光拡散層（例えば後述する図５の光拡散層３６参照）を蛍光体層２５（または蛍光体層２５の液晶表示パネル１０側に設けられた保護層２６ａ）の液晶表示パネル１０側に設けてもよい。図５に示すように第１接着層４０ａおよび光拡散層を併用してもよいし、第１接着層４０ａに代えて光拡散層を設けてもよい。光拡散層は、光学層積層体を構成する光学層のうち、蛍光体層２５の最も近くに形成されていることが好ましい。 As described above, if an air layer is formed between the phosphor layer 25 (or the protective layer 26 a provided on the liquid crystal display panel 10 side of the phosphor layer 25) and the optical layer laminate 30, the excitation light It is considered that the usage efficiency can be improved, and thereby the brightness of the liquid crystal display device can be improved. The structure of the optical layer laminate 30 is not limited to the illustrated one. Of the optical layers constituting the optical layer laminate, the layer closest to the phosphor layer 25 may be a prism sheet, or a polarization selective reflection layer, a polarization layer, a light diffusion layer, a transparent sheet, a protective layer, and the like. It can be any layer. From the viewpoint of improving the utilization efficiency of the excitation light, it is only necessary to improve the rate at which the excitation light that has passed through the phosphor layer 25 and is emitted toward the liquid crystal display panel 10 enters the phosphor layer 25 again. Therefore, the present invention is not limited to the first adhesive layer 40a forming the air layer shown in FIG. May be provided on the liquid crystal display panel 10 side of the protective layer 26a) provided on the liquid crystal display panel 10 side. As shown in FIG. 5, the first adhesive layer 40a and the light diffusion layer may be used together, or a light diffusion layer may be provided instead of the first adhesive layer 40a. The light diffusion layer is preferably formed closest to the phosphor layer 25 among the optical layers constituting the optical layer laminate.
　なお、ここでは、蛍光体層２５が量子ドット蛍光体２５ｑを含む例を説明したが、本発明の実施形態はこれに限られない。励起光の利用効率を向上させることができるという効果が得られるのもこの場合に限られない。 Here, an example in which the phosphor layer 25 includes the quantum dot phosphor 25q has been described, but the embodiment of the present invention is not limited to this. The effect that the utilization efficiency of the excitation light can be improved is not limited to this case.
　以下、液晶表示装置１００の構成（特にバックライト装置５０の構成）をより具体的に説明する。 Hereinafter, the configuration of the liquid crystal display device 100 (particularly, the configuration of the backlight device 50) will be described more specifically.
　バックライト装置５０は、発光素子（ＬＥＤチップ２２）から離れて蛍光体（蛍光体層２５）を配置するリモートフォスファー方式である。ＬＥＤチップ２２および蛍光体層２５は、液晶表示パネル１０の背面１０ｒに向けて白色の光を出射する。ＬＥＤチップ２２から出射された光が、蛍光体層２５中の蛍光体を励起し、光（蛍光またはりん光）が発せられる。例えば、ＬＥＤチップ２２が青色の光を出射する青色ＬＥＤチップである場合、蛍光体層２５は、緑色蛍光を発する蛍光体および／または赤色蛍光を発する蛍光体を含んでもよいし、黄色蛍光を発する蛍光体を含んでもよい。高い演色性を得る観点からは、蛍光体層２５は、緑色蛍光を発する蛍光体および／または赤色蛍光を発する蛍光体を含むことが好ましい。蛍光体層２５は、例えば、緑色蛍光を発する量子ドット蛍光体および／または赤色蛍光を発する量子ドット蛍光体を含んでもよい。量子ドット蛍光体は、一般的に、発光スペクトルのピーク波長の半値幅が狭く、色純度が高いという利点を有するので、例えばＵＨＤ　Ｐｒｅｍｉｕｍ規格（色再現性ＢＴ２０２０規格９０％以上、ＨＤＲ１０規格）を満たすために有望であるとされている。あるいは、赤色硫化物蛍光体（例えば硫化カルシウム蛍光体）、緑色硫化物蛍光体（例えばチオガレート蛍光体）など、公知の蛍光体を用いてもよい。蛍光体層２５および保護層２６ａ、２６ｂの厚さは、例えば、それぞれ１００μｍ程度であり、蛍光体層２５および保護層２６ａ、２６ｂの厚さの和は、例えば３００μｍ程度である。 The backlight device 50 is of a remote phosphor type in which a phosphor (phosphor layer 25) is arranged apart from the light emitting element (LED chip 22). The LED chip 22 and the phosphor layer 25 emit white light toward the back surface 10r of the liquid crystal display panel 10. The light emitted from the LED chip 22 excites the phosphor in the phosphor layer 25 to emit light (fluorescence or phosphorescence). For example, when the LED chip 22 is a blue LED chip that emits blue light, the phosphor layer 25 may include a phosphor that emits green fluorescence and / or a phosphor that emits red fluorescence, or emits yellow fluorescence. A phosphor may be included. From the viewpoint of obtaining high color rendering properties, the phosphor layer 25 preferably contains a phosphor that emits green fluorescence and / or a phosphor that emits red fluorescence. The phosphor layer 25 may include, for example, a quantum dot phosphor that emits green fluorescence and / or a quantum dot phosphor that emits red fluorescence. Quantum dot phosphors generally have the advantage that the half width of the peak wavelength of the emission spectrum is narrow and the color purity is high, and therefore, for example, satisfy the UHD @ Premium standard (color reproducibility BT2020 standard 90% or more, HDR10 standard). It has been shown to be promising. Alternatively, a known phosphor such as a red sulfide phosphor (for example, calcium sulfide phosphor) and a green sulfide phosphor (for example, thiogallate phosphor) may be used. The thickness of the phosphor layer 25 and the protective layers 26a, 26b is, for example, about 100 μm, respectively, and the sum of the thicknesses of the phosphor layer 25 and the protective layers 26a, 26b is, for example, about 300 μm.
　波長選択反射層（ダイクロイック・フィルタ）２８は、ＬＥＤチップ２２から出射された光の波長領域の少なくとも一部を透過し、蛍光体層２５から発せられた光（蛍光またはりん光）の少なくとも一部を反射する。好ましくは、波長選択反射層２８は、ＬＥＤチップ２２から出射された光の全てを透過し、蛍光体層２５から発せられた光の全てを反射する。例えばＬＥＤチップ２２が青色ＬＥＤである場合、波長選択反射層２８は、青色ＬＥＤの発光波長領域（すなわち青色）の光を透過し、緑色から赤色にかけての波長領域の光を反射する。波長選択反射層２８は、例えば、屈折率の異なる膜を積層した積層構造を有する光学多層膜である。 The wavelength selective reflection layer (dichroic filter) 28 transmits at least a part of the wavelength region of the light emitted from the LED chip 22 and at least a part of the light (fluorescence or phosphorescence) emitted from the phosphor layer 25. Is reflected. Preferably, the wavelength selective reflection layer 28 transmits all of the light emitted from the LED chip 22 and reflects all of the light emitted from the phosphor layer 25. For example, when the LED chip 22 is a blue LED, the wavelength selective reflection layer 28 transmits light in the emission wavelength region (that is, blue) of the blue LED and reflects light in the wavelength region from green to red. The wavelength selective reflection layer 28 is, for example, an optical multilayer film having a laminated structure in which films having different refractive indexes are laminated.
　液晶表示装置１００は、波長選択反射層２８を有することによって、部分駆動を行った場合と行わない場合の両方において、色むらを抑制することができる。液晶表示装置１００の複数のＬＥＤチップ２２は、部分駆動を行ってもよいし、行わなくてもよい。部分駆動を行った場合は、比較例１のバックライト装置９５０と同様に、図９を参照しながら説明した比較例２のバックライト装置９５０Ｒにおいて生じる色むらを抑制することができる。部分駆動を行わない場合について図１０を参照して以下で説明する。 (4) Since the liquid crystal display device 100 includes the wavelength selective reflection layer 28, color unevenness can be suppressed both when the partial driving is performed and when the partial driving is not performed. The plurality of LED chips 22 of the liquid crystal display device 100 may or may not be partially driven. When partial driving is performed, similarly to the backlight device 950 of Comparative Example 1, it is possible to suppress color unevenness that occurs in the backlight device 950R of Comparative Example 2 described with reference to FIG. A case in which the partial drive is not performed will be described below with reference to FIG.
　本発明者の検討によると、図１０（ａ）に示すように、比較例２のバックライト装置９５０Ｒを用いると、部分駆動を行わない場合においても色むらが生じることがある。図１０（ｂ）に、比較例２の液晶表示装置９００Ｒにおいて、全面白表示を行った場合に表示される画像パターンを模式的に示す。図１０（ｂ）は、液晶表示装置９００Ｒが有する液晶表示パネルの法線方向から見たときの模式的な図である。 According to the study of the present inventor, as shown in FIG. 10A, when the backlight device 950R of Comparative Example 2 is used, color unevenness may occur even when partial driving is not performed. FIG. 10B schematically shows an image pattern displayed when white display is performed on the entire surface of the liquid crystal display device 900R of Comparative Example 2. FIG. 10B is a schematic view when the liquid crystal display panel of the liquid crystal display device 900R is viewed from the normal direction.
　図１０（ｂ）に示すように、全面白表示を行っても（すなわち液晶表示パネルの全ての画素に白を表示させる階調を入力しても）、発光素子９１０に重なる領域に比べて、その周辺の領域（図中の左下がりハッチング部）の黄色味が強くなってしまうことがある。これは、図１０（ａ）に示すように、発光素子９１０から出射され、蛍光体シート９２０に垂直に（入射角０°で）入射する光Ｌaの蛍光体シート９２０中の光路長ＯＬaよりも、発光素子９１０から出射され、蛍光体シート９２０に有限の入射角で入射する光Ｌbの蛍光体シート９２０中の光路長ＯＬbの方が長いことに起因している。これにより、光Ｌbの方が光Ｌaよりも蛍光体シート９２０中の蛍光体を励起する確率が高いので、赤色から緑色にかけての波長領域の光を多く発光する。従って、液晶表示パネルの法線方向から見たとき、発光素子９１０の周辺の領域において、黄色味が強くなる。 As shown in FIG. 10B, even when performing full white display (that is, even when inputting a gray level for displaying white to all the pixels of the liquid crystal display panel), compared with the region overlapping with the light emitting element 910, In some cases, the yellow color of the peripheral area (hatched portion on the lower left in the figure) becomes strong. This is because, as shown in FIG. 10 (a), emitted from the light emitting element 910, the optical path length OL a in the phosphor sheet 920 of the light L a to vertically (at an incident angle 0 °) incident on the phosphor sheet 920 than is emitted from the light emitting element 910, toward the optical path length OL b in the phosphor sheet 920 of the light L b at an incident angle of finite phosphor sheet 920 is due to a long time. Accordingly, the light for L b is high, and thus the probability to excite the phosphor in the phosphor sheet 920 than the light L a, emits more light in the wavelength region of toward green from red. Therefore, when viewed from the normal direction of the liquid crystal display panel, yellowish color becomes strong in a region around the light emitting element 910.
　これに対して、液晶表示装置１００は波長選択反射層２８を有するので、蛍光体層２５から後方（ＬＥＤ基板２１側）に発せられた光は、波長選択反射層２８で反射され、液晶表示パネル１０の背面１０ｒに向かって発せられる。これにより、液晶表示パネル１０の法線方向から見たとき、ＬＥＤチップ２２に重なる領域において、赤色から緑色にかけての波長領域の光が強められる。従って、ＬＥＤチップ２２に重なる領域とその周辺領域との色味の違いが緩和され、色むらが軽減される。 On the other hand, since the liquid crystal display device 100 has the wavelength selection reflection layer 28, light emitted from the phosphor layer 25 backward (toward the LED substrate 21) is reflected by the wavelength selection reflection layer 28, and It is emitted toward the back surface 10r of 10. As a result, when viewed from the normal direction of the liquid crystal display panel 10, light in a wavelength region from red to green is enhanced in a region overlapping the LED chip 22. Therefore, the difference in tint between the area overlapping the LED chip 22 and the surrounding area is reduced, and color unevenness is reduced.
　液晶表示装置１００は、第１接着層４０ａが空気層を形成していることによっても、部分駆動を行わない場合の色むらを軽減する効果が得られる。励起光の利用効率を向上させることによって、ＬＥＤチップ２２に重なる領域において、赤色および緑色の蛍光の発光が強められる。 The liquid crystal display device 100 has an effect of reducing color unevenness when partial driving is not performed even when the first adhesive layer 40a forms an air layer. By improving the utilization efficiency of the excitation light, the emission of the red and green fluorescent light is enhanced in the region overlapping the LED chip 22.
　本発明の実施形態は上記の例に限られない。例えば、ＬＥＤチップ２２は、マゼンタ色の光を発してもよい。つまり、ＬＥＤチップ２２は、青色ＬＥＤチップの発光面上に、赤色蛍光体を分散させた分散媒（樹脂）が付与された構造を有してもよい。この場合、青色ＬＥＤチップから発せられた青色の光が赤色蛍光体を励起して赤色の光が発せられる。ＬＥＤチップ２２全体からは青色の光と赤色の光とが発せられ、マゼンタ色の光が発せられるように見える。このような場合、蛍光体層２５は緑色蛍光体を含めばよく、波長選択反射層２８は、青色および赤色の光を透過し、緑色の光を反射するものであればよい。 実 施 Embodiments of the present invention are not limited to the above examples. For example, the LED chip 22 may emit magenta light. That is, the LED chip 22 may have a structure in which a dispersion medium (resin) in which a red phosphor is dispersed is provided on the light emitting surface of the blue LED chip. In this case, the blue light emitted from the blue LED chip excites the red phosphor to emit red light. The entire LED chip 22 emits blue light and red light, and appears to emit magenta light. In such a case, the phosphor layer 25 only needs to include a green phosphor, and the wavelength selective reflection layer 28 only needs to transmit blue and red light and reflect green light.
　複数のＬＥＤチップ２２は、例えば、ＬＥＤ基板２１の表面２１ｓに、マトリクス状に配列されている。ＬＥＤ基板２１は、例えばシャーシが兼ねてもよいし、液晶表示装置１００は、シャーシ（不図示）をさらに有してもよい。複数のＬＥＤチップ２２は、ＬＥＤ基板２１にベアチップ実装されていてもよい。すなわち、ＬＥＤチップ２２のそれぞれは光学レンズに覆われていなくてもよい。複数のＬＥＤチップ２２がベアチップ実装されていると、以下の利点を得られる。 (4) The plurality of LED chips 22 are arranged in a matrix on the surface 21s of the LED substrate 21, for example. The LED board 21 may serve as, for example, a chassis, and the liquid crystal display device 100 may further include a chassis (not shown). The plurality of LED chips 22 may be mounted on the LED substrate 21 as bare chips. That is, each of the LED chips 22 may not be covered with the optical lens. When a plurality of LED chips 22 are mounted as bare chips, the following advantages can be obtained.
　比較例１のバックライト装置９５０の構成を検討したところ、バックライト装置９５０を備えた比較例１の液晶表示装置９００において、輝度むらが生じる場合があることが分かった。輝度むらは、複数の発光素子９１０のピッチＰに対する、ＬＥＤ基板９０１と拡散板９４０との間の距離Ｄ１の比（Ｄ１／Ｐ）が所定の値よりも小さいことに起因して生じる。輝度むらの発生を抑制する観点からは、例えば、Ｄ１／Ｐは０．２５以上であることが好ましい。 と こ ろ When the configuration of the backlight device 950 of Comparative Example 1 was examined, it was found that in the liquid crystal display device 900 of Comparative Example 1 including the backlight device 950, luminance unevenness sometimes occurred. The uneven brightness occurs because the ratio (D1 / P) of the distance D1 between the LED substrate 901 and the diffusion plate 940 to the pitch P of the plurality of light emitting elements 910 is smaller than a predetermined value. From the viewpoint of suppressing the occurrence of uneven brightness, for example, D1 / P is preferably 0.25 or more.
　一般に、複数の発光素子（例えばＬＥＤチップ）９１０のそれぞれは、所望の配光特性を得るために、光学レンズで覆われていることが多い。光学レンズの最小径は、設計上の制約から１０ｍｍ程度である。したがって、例えば、光学レンズで覆われている複数の発光素子９１０のピッチを、光学レンズのレンズ径の２倍とすると、複数の発光素子９１０のピッチＰは最小でも２０ｍｍ程度となる。そうすると、Ｄ１／Ｐを０．２５以上に設定するためには、ＬＥＤ基板９０１と拡散板９４０との間の距離Ｄ１を５ｍｍより小さくすることができないことになる。拡散板９４０の厚さは数ｍｍであることが一般的であるので、バックライト装置９５０の薄型化に限界がある。また、上述したように、ＬＥＤ基板９０１の表面（複数の発光素子９１０を有する面）は、輝度を高めるために、発光素子９１０の間に反射シートを有することがある。反射シートを設ける領域の広さを確保するために、発光素子９１０のピッチを大きくすることが好ましい場合もある。さらに、特許文献１には、輝度むらを抑制する観点および蛍光体シート９２０への熱の影響を抑制する観点から、蛍光体シート９２０と複数の発光素子９１０との間の距離は１０ｍｍ以上であることが望ましいと記載されている。 Generally, each of the plurality of light emitting elements (for example, LED chips) 910 is often covered with an optical lens in order to obtain desired light distribution characteristics. The minimum diameter of the optical lens is about 10 mm due to design restrictions. Therefore, for example, if the pitch of the plurality of light emitting elements 910 covered by the optical lens is twice the lens diameter of the optical lens, the pitch P of the plurality of light emitting elements 910 is at least about 20 mm. Then, in order to set D1 / P to 0.25 or more, the distance D1 between the LED substrate 901 and the diffusion plate 940 cannot be made smaller than 5 mm. Since the thickness of the diffusion plate 940 is generally several mm, the thickness of the backlight device 950 is limited. Further, as described above, the surface of the LED substrate 901 (the surface having the plurality of light-emitting elements 910) may have a reflective sheet between the light-emitting elements 910 in order to increase luminance. In some cases, it is preferable to increase the pitch of the light emitting elements 910 in order to secure the area of the region where the reflective sheet is provided. Further, in Patent Literature 1, the distance between the phosphor sheet 920 and the plurality of light emitting elements 910 is 10 mm or more from the viewpoint of suppressing luminance unevenness and suppressing the influence of heat on the phosphor sheet 920. It is stated that it is desirable.
　これに対して、液晶表示装置１００のＬＥＤチップ２２がＬＥＤ基板２１にベアチップ実装されていると（すなわち、裸のＬＥＤチップ２２がＬＥＤ基板２１の表面２１ｓ上に複数個配列されていると）、複数のＬＥＤチップ２２のピッチＰを２０ｍｍ以下にすることができる。これにより、輝度むらの発生を抑制しながら、ＬＥＤ基板２１と波長選択反射層２８との間の距離Ｄを５ｍｍ以下にすることができる。液晶表示装置１００は、輝度むらの発生を抑制しつつ、比較例１の液晶表示装置９００に比べて薄型化することができる。 On the other hand, if the LED chips 22 of the liquid crystal display device 100 are bare-chip mounted on the LED substrate 21 (that is, if a plurality of bare LED chips 22 are arranged on the surface 21s of the LED substrate 21), The pitch P between the plurality of LED chips 22 can be set to 20 mm or less. This makes it possible to reduce the distance D between the LED substrate 21 and the wavelength selective reflection layer 28 to 5 mm or less while suppressing the occurrence of uneven brightness. The liquid crystal display device 100 can be made thinner than the liquid crystal display device 900 of Comparative Example 1, while suppressing the occurrence of uneven brightness.
　さらに、液晶表示装置１００において、複数のＬＥＤチップ２２のピッチＰを２０ｍｍ以下と小さくすることで、複数のＬＥＤチップ２２のピッチＰに対する、ＬＥＤ基板２１と波長選択反射層２８との間の距離Ｄの比（Ｄ／Ｐ）を０．８以上とすれば、十分に輝度むらおよび色むらを抑制することができることが分かった。すなわち、液晶表示装置１００は、ＬＥＤ基板２１と波長選択反射層２８との間の光拡散層も、ＬＥＤ基板２１の表面２１ｓの反射部材も、ＬＥＤチップ２２を覆う光学レンズも有することなく、十分に輝度むらおよび色むらを抑制することができることが分かった。 Further, in the liquid crystal display device 100, by reducing the pitch P between the plurality of LED chips 22 to 20 mm or less, the distance D between the LED substrate 21 and the wavelength selective reflection layer 28 with respect to the pitch P between the plurality of LED chips 22 is reduced. It was found that when the ratio (D / P) was 0.8 or more, it was possible to sufficiently suppress luminance unevenness and color unevenness. That is, the liquid crystal display device 100 is sufficiently provided without having a light diffusion layer between the LED substrate 21 and the wavelength selective reflection layer 28, a reflection member on the surface 21s of the LED substrate 21, and an optical lens covering the LED chip 22. It was found that uneven brightness and uneven color can be suppressed.
　ＬＥＤ基板２１の表面２１ｓの複数のＬＥＤチップ２２の間には、蛍光および励起光を反射する反射部材を有しなくてもよい。ここで、「反射部材」は、入射角０°～４５°の範囲における、受光角２πステラジアンの半球領域における全光線反射率（正反射率と拡散反射率の合計）が８０％以上のものをいうことにする。このような全光線反射率は、例えばRADIANT社製の散乱・外観測定システムIS-SAを用いて計測することができる。バックライト装置５０は、波長選択反射層２８を有するので、反射部材を有しないことによる輝度の低下の影響は小さい。ＬＥＤ基板２１の表面２１ｓの複数のＬＥＤチップ２２の間には、蛍光を吸収する吸収部材が設けられていてもよい。吸収部材を設けると、図９を参照しながら説明した比較例２のバックライト装置９５０Ｒにおいて生じる部分駆動時の色むらを抑制することが簡単になる。すなわち、蛍光体層２５から後方（ＬＥＤ基板２１側）に発せられた光がＬＥＤ基板２１の表面２１ｓで反射され、再び蛍光体層２５に入射する光が少なくなるので、その影響が小さくなるからである。 反射 A reflective member that reflects fluorescence and excitation light may not be provided between the plurality of LED chips 22 on the surface 21s of the LED substrate 21. Here, the “reflecting member” is defined as a member having a total light reflectance (the sum of the regular reflectance and the diffuse reflectance) of 80% or more in a hemispherical region having a light receiving angle of 2π steradian in an incident angle range of 0 ° to 45 °. I will say. Such total light reflectance can be measured using, for example, a scattering / appearance measurement system IS-SA manufactured by RADIANT. Since the backlight device 50 has the wavelength selective reflection layer 28, the influence of the decrease in luminance due to the absence of the reflection member is small. An absorbing member that absorbs fluorescence may be provided between the plurality of LED chips 22 on the surface 21s of the LED substrate 21. By providing the absorbing member, it becomes easy to suppress the color unevenness at the time of the partial driving that occurs in the backlight device 950R of Comparative Example 2 described with reference to FIG. That is, light emitted backward from the phosphor layer 25 (on the side of the LED substrate 21) is reflected by the surface 21s of the LED substrate 21, and the amount of light incident on the phosphor layer 25 again decreases, so that the effect is reduced. It is.
　本発明の実施形態のさらに他の例を図５に示す。図５は、光学層積層体３０Ｂを有する液晶表示装置１００Ｂを模式的に示す断面図である。 FIG. 5 shows still another example of the embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing a liquid crystal display device 100B having an optical layer laminate 30B.
　図５に示すように、液晶表示装置１００Ｂは、光学層積層体３０Ｂを有する点において、液晶表示装置１００と異なる。光学層積層体３０Ｂは、光拡散層３６をさらに有する点において、光学層積層体３０と異なる。光拡散層３６は、偏光選択反射層３２よりも、ＬＥＤ基板２１の近くに配置されている。光拡散層３６は、例えば、ベースフィルム（例えばＰＥＴフィルム）３６ｂとベースフィルム３６ｂ上に付与された光拡散材（例えば球状のビーズ）３６ｄとを有する。 液晶 As shown in FIG. 5, the liquid crystal display device 100B differs from the liquid crystal display device 100 in having an optical layer laminate 30B. The optical layer laminate 30B differs from the optical layer laminate 30 in further including a light diffusion layer 36. The light diffusion layer 36 is disposed closer to the LED substrate 21 than the polarization selective reflection layer 32 is. The light diffusion layer 36 has, for example, a base film (for example, a PET film) 36b and a light diffusion material (for example, spherical beads) 36d provided on the base film 36b.
　光学層積層体３０Ｂにおいても、例えば、２枚のプリズムシート３４ａおよび３４ｂのうち、蛍光体層２５に近い方のプリズムシート３４ｂの、ＬＥＤ基板２１を向く表面は鏡面である。 Also in the optical layer laminate 30B, for example, of the two prism sheets 34a and 34b, the surface of the prism sheet 34b closer to the phosphor layer 25 facing the LED substrate 21 is a mirror surface.
　液晶表示装置１００Ｂは、図１に示した液晶表示装置１００と同様に、バックライト装置５０の液晶表示パネル１０側に配置される光学シートと、液晶表示パネル１０との間に空隙が形成されないので、従来の液晶表示装置よりも薄くできる。さらに、液晶表示装置１００Ｂは、光拡散層をＬＥＤ基板２１と波長選択反射層２８との間に有しないので、さらに薄型化することができる。 In the liquid crystal display device 100B, similarly to the liquid crystal display device 100 shown in FIG. 1, no gap is formed between the liquid crystal display panel 10 and the optical sheet disposed on the liquid crystal display panel 10 side of the backlight device 50. , And can be thinner than a conventional liquid crystal display device. Further, since the liquid crystal display device 100B does not have the light diffusion layer between the LED substrate 21 and the wavelength selective reflection layer 28, the thickness can be further reduced.
　液晶表示装置１００Ｂも、図３を参照して説明した液晶表示装置１００と同様に、液晶表示装置１００Ｒに比べて、輝度を向上させることができる。これについて、図６を参照して説明する。図６は、液晶表示装置１００Ｂの模式的な断面図であり、図５の一部を拡大して示す図である。 {Circle around (3)} The liquid crystal display device 100B can also improve the luminance as compared with the liquid crystal display device 100R, like the liquid crystal display device 100 described with reference to FIG. This will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view of the liquid crystal display device 100B, and is an enlarged view of a part of FIG.
　図６に示すように、励起光Ｌａの一部は、蛍光体層２５から液晶表示パネル１０に向かって発せられるとき、保護層２６ａと第１接着層４０ａが形成する空気層との界面で反射され、再び蛍光体層２５に入射する。さらに、第１接着層４０ａが形成する空気層と光拡散層３６のベースフィルム３６ｂとの界面においても反射される。光拡散材３６ｄの屈折率とベースフィルム３６ｂの屈折率の差が大きければ、光拡散材３６ｄの表面においても反射され得る。光拡散層３６による拡散反射によっても、励起光が再び蛍光体層２５に入射する効果が強められ得る。従って、励起光の利用効率を向上させる効果および部分駆動を行わない場合の色むらを軽減する効果が大きい。 As shown in FIG. 6, when part of the excitation light La is emitted from the phosphor layer 25 toward the liquid crystal display panel 10, it is reflected at the interface between the protective layer 26a and the air layer formed by the first adhesive layer 40a. Then, the light enters the phosphor layer 25 again. Further, the light is also reflected at the interface between the air layer formed by the first adhesive layer 40a and the base film 36b of the light diffusion layer 36. If the difference between the refractive index of the light diffusing material 36d and the refractive index of the base film 36b is large, the light can also be reflected on the surface of the light diffusing material 36d. The effect of the excitation light being incident on the phosphor layer 25 again can also be enhanced by the diffuse reflection by the light diffusion layer 36. Therefore, the effect of improving the use efficiency of the excitation light and the effect of reducing the color unevenness when the partial driving is not performed are large.
　液晶表示装置１００を製造する方法を、例を挙げて説明する。 (4) A method for manufacturing the liquid crystal display device 100 will be described with an example.
　液晶表示装置１００の製造方法は、例えば以下の工程を包含する。
　　工程I：液晶表示パネル１０を用意する。
　　工程II：工程Iの後に、液晶表示パネル１０の背面１０ｒ上に、光学層積層体３０、蛍光体層２５および波長選択反射層２８を複数の接着層４０ａ、４０ｂ、４０ｃを介して一体に固定する。
　　工程III：複数のＬＥＤチップ２２が表面２１ｓに配列されたＬＥＤ基板２１を用意する。
　　工程IV：工程IIおよび工程IIIの後に、液晶表示パネル１０の背面１０ｒに複数のＬＥＤチップ２２が向くように、液晶表示パネル１０とＬＥＤ基板２１とを固定する。 The method for manufacturing the liquid crystal display device 100 includes, for example, the following steps.
Step I: A liquid crystal display panel 10 is prepared.
Step II: After step I, the optical layer laminate 30, the phosphor layer 25, and the wavelength selective reflection layer 28 are integrally fixed on the back surface 10r of the liquid crystal display panel 10 via the plurality of adhesive layers 40a, 40b, and 40c. I do.
Step III: Prepare an LED substrate 21 on which a plurality of LED chips 22 are arranged on the front surface 21s.
Step IV: After the steps II and III, the liquid crystal display panel 10 and the LED substrate 21 are fixed so that the plurality of LED chips 22 face the rear surface 10r of the liquid crystal display panel 10.
　工程IIは、例えば、以下の工程を包含する。
　　工程IIａ：蛍光体層２５と波長選択反射層２８とを一体に固定する。
　　工程IIｂ：液晶表示パネル１０の背面１０ｒ上に、光学層積層体３０を固定する。
　　工程IIｃ：工程IIａおよび工程IIｂの後に、光学層積層体３０と蛍光体層２５とを貼り合せる。
　この場合、液晶表示装置１００の製造コストを抑えることができる場合がある。蛍光体層２５を有する液晶表示装置１００と、蛍光体層を有しない液晶表示装置とを製造する工場においては、上記の製造プロセスを採用すると、液晶表示装置１００を製造する場合にのみ工程IIｃを行えばよいので、製造管理を効率的に行うことができる。 Step II includes, for example, the following steps.
Step IIa: The phosphor layer 25 and the wavelength selective reflection layer 28 are integrally fixed.
Step IIb: The optical layer laminate 30 is fixed on the back surface 10r of the liquid crystal display panel 10.
Step IIc: After the step IIa and the step IIb, the optical layer laminate 30 and the phosphor layer 25 are bonded.
In this case, the manufacturing cost of the liquid crystal display device 100 may be reduced in some cases. In a factory that manufactures the liquid crystal display device 100 having the phosphor layer 25 and the liquid crystal display device having no phosphor layer, if the above manufacturing process is adopted, the step IIc is performed only when the liquid crystal display device 100 is manufactured. Since it suffices to perform the process, the production management can be performed efficiently.
　あるいは、工程IIは、光学層積層体３０、蛍光体層２５および波長選択反射層２８を一体に固定した後、これらを液晶表示パネル１０の背面１０ｒに固定する工程を包含してもよい。この場合、蛍光体層２５と波長選択反射層２８とを一体に固定した後、光学層積層体３０と一体化してもよいし、光学層積層体３０と蛍光体層２５とを一体に固定した後、波長選択反射層２８と一体化してもよい。 Alternatively, the step II may include a step of fixing the optical layer laminate 30, the phosphor layer 25, and the wavelength selective reflection layer 28 integrally, and then fixing them to the rear surface 10r of the liquid crystal display panel 10. In this case, after the phosphor layer 25 and the wavelength selective reflection layer 28 are integrally fixed, the phosphor layer 25 and the wavelength selective reflection layer 28 may be integrated with the optical layer laminate 30, or the optical layer laminate 30 and the phosphor layer 25 may be integrally fixed. After that, it may be integrated with the wavelength selective reflection layer 28.
　工程IIにおいて、光学層積層体３０と蛍光体層２５とを互いに接着する工程は、例えば、ベースフィルムとベースフィルムの両側に形成された２つの接着層とを有する両面接着フィルムを用いて行われる。ベースフィルムの両側に接着層が設けられた、いわゆる両面接着フィルムを用いると、アセンブリ工程を単純にできる。ベースフィルムの両側に形成された２つの接着層の一方は、第１接着層（ドット接着層）４０ａであり、他方は、ベースフィルムの全面に連続的に形成された接着層である。２つの接着層のうちの光学層積層体３０に近い方の接着層が、第１接着層４０ａ、すなわち離散的に配置された複数の接着部４０ｐを有する接着層であると、光の利用効率をより（例えば逆の配置よりも）高めることができる。 In the step II, the step of bonding the optical layer laminate 30 and the phosphor layer 25 to each other is performed using, for example, a double-sided adhesive film having a base film and two adhesive layers formed on both sides of the base film. . When a so-called double-sided adhesive film in which an adhesive layer is provided on both sides of the base film is used, the assembly process can be simplified. One of the two adhesive layers formed on both sides of the base film is a first adhesive layer (dot adhesive layer) 40a, and the other is an adhesive layer continuously formed on the entire surface of the base film. When the adhesive layer closer to the optical layer laminate 30 of the two adhesive layers is the first adhesive layer 40a, that is, the adhesive layer having a plurality of discretely arranged adhesive portions 40p, the light use efficiency is improved. (E.g., more than the reverse arrangement).
　あるいは、光学層積層体３０と蛍光体層２５とを互いに接着する工程は、両面接着フィルムを用いずに行われてもよい。例えば、光学層積層体３０と蛍光体層２５とを互いに接着する工程は、上記の第１接着層４０ａ、すなわち離散的に配置された複数の接着部４０ｐを有する接着層の両側に、光学層積層体３０および蛍光体層２５を接触させる工程を包含してもよい。 Alternatively, the step of bonding the optical layer laminate 30 and the phosphor layer 25 to each other may be performed without using a double-sided adhesive film. For example, the step of adhering the optical layer laminate 30 and the phosphor layer 25 to each other includes the above-mentioned first adhesive layer 40a, that is, an optical layer on both sides of an adhesive layer having a plurality of discretely arranged adhesive portions 40p. A step of bringing the laminate 30 and the phosphor layer 25 into contact may be included.
　光学層積層体３０と蛍光体層２５とを互いに接着する工程は、光学層積層体３０の一面に接着層を付与した後、蛍光体層２５と一体化してもよいし、蛍光体層２５の一面に接着層を付与した後、光学層積層体３０と一体化してもよい。 In the step of bonding the optical layer laminate 30 and the phosphor layer 25 to each other, the adhesive layer may be provided on one surface of the optical layer laminate 30 and then integrated with the phosphor layer 25 or the phosphor layer 25 may be integrated. After the adhesive layer is provided on one surface, the adhesive layer may be integrated with the optical layer laminate 30.
　本発明者は、実施例１～４および比較例の液晶表示装置を以下のように作製し、最高階調を呈した場合の輝度および色度を分光放射輝度計（株式会社トプコンテクノハウス製の分光放射計SR-LEDW）を用いて測定した。実施例１は、図１に示した液晶表示装置１００と同じ構造を有し、実施例２および３は、図５に示した液晶表示装置１００Ｂと同じ構造を有し、実施例４は、図３に示した液晶表示装置１００Ｒと同じ構造を有する。実施例２および３は、第１接着層４０ａの接着部４０ｐのピッチおよび大きさにおいて異なる。実施例４は、空気層を形成しない第１接着層４０Ｒを有する点において、実施例１と異なる。 The inventor manufactured the liquid crystal display devices of Examples 1 to 4 and Comparative Example as follows, and measured the luminance and chromaticity when the highest gradation was exhibited by using a spectral radiance meter (manufactured by Topcon Technohouse Co., Ltd.). It was measured using a spectroradiometer (SR-LEDW). Example 1 has the same structure as the liquid crystal display device 100 shown in FIG. 1, Examples 2 and 3 have the same structure as the liquid crystal display device 100B shown in FIG. It has the same structure as the liquid crystal display device 100R shown in FIG. Embodiments 2 and 3 differ in the pitch and size of the bonding portion 40p of the first bonding layer 40a. The fourth embodiment differs from the first embodiment in having a first adhesive layer 40R in which no air layer is formed.
　比較例は、図１１に示す液晶表示装置９００Ｂと同じ構造を有する。液晶表示装置９００Ｂ（比較例）が有するバックライト装置９５０Ｂは、光学層積層体９６０を有する点において、図８（ｂ）に示した液晶表示装置９００が有するバックライト装置９５０と異なる。光学層積層体９６０は、図１に示した液晶表示装置１００が有する光学層積層体３０と同様の構造を有し、２枚のプリズムシート９６４ａおよび９６４ｂと、これらの上に配置された偏光選択反射層９６２とを含む。また、光学層積層体９６０と蛍光体シート９２０との間、蛍光体シート９２０と波長選択性反射膜９３０との間、および、波長選択性反射膜９３０と拡散板９４０との間には、接着層は配置されておらず、空気層Ｓ１、Ｓ２およびＳ３がそれぞれ形成されている。すなわち、拡散板９４０の上に、波長選択性反射膜９３０、蛍光体シート９２０および光学層積層体９６０が、この順で積み重ねられて載せられている。なお、液晶表示パネル９９０は、液晶セル９９１と、液晶セル９９１の両側に設けられた偏光板９９２ａおよび９９２ｂとを有する。 The comparative example has the same structure as the liquid crystal display device 900B shown in FIG. The backlight device 950B included in the liquid crystal display device 900B (comparative example) is different from the backlight device 950 included in the liquid crystal display device 900 illustrated in FIG. The optical layer laminate 960 has a structure similar to that of the optical layer laminate 30 included in the liquid crystal display device 100 shown in FIG. 1, and includes two prism sheets 964a and 964b and a polarization selector disposed thereon. A reflective layer 962. Further, an adhesive is provided between the optical layer laminate 960 and the phosphor sheet 920, between the phosphor sheet 920 and the wavelength-selective reflective film 930, and between the wavelength-selective reflective film 930 and the diffusion plate 940. No layers are arranged and air layers S1, S2 and S3 are each formed. That is, on the diffusion plate 940, the wavelength-selective reflection film 930, the phosphor sheet 920, and the optical layer laminate 960 are stacked and placed in this order. Note that the liquid crystal display panel 990 includes a liquid crystal cell 991 and polarizing plates 992a and 992b provided on both sides of the liquid crystal cell 991.
　・実施例１（液晶表示パネル１０の前面側から順に）
　　偏光板１１ａ（保護ラミネートあり、厚さ２３０μｍ）
　　液晶セル１（厚さ１２００μｍ、ガラス基板の透過率１．４９）
　　偏光板１１ｂ（保護ラミネートなし、厚さ１６６μｍ）
　　光学層積層体３０：GLOTEC社製 GD221（DPOP：光学複合機能シート）
　　　光学層積層体３０の厚さ：３８０μｍ
　　第１接着層４０ａ：DIC株式会社製のTN20AIR
　　　複数の接着部４０ｐのピッチ800μm、接着部４０ｐのドット径300μm
　　　第１接着層４０ａにおける複数の接着部４０ｐの占有面積率：５０％
　　　第１接着層４０ａの屈折率：１．４９程度
　　　第１接着層４０ａの厚さ：２５μｍ
　　蛍光体層２５および保護層２６ａ、２６ｂ：日立化成株式会社製　量子ドットフィルム
　　　蛍光体層２５および保護層２６ａ、２６ｂの厚さの和：３６０μｍ
　　接着層４０ｂ（厚さ２５μｍ）
　　波長選択反射層２８：東レ株式会社製　Ｐｉｃａｓｕｓ シート
　　　波長選択反射層２８の厚さ：７０μｍ
　　保護層（厚さ６０μｍ） -Example 1 (in order from the front side of the liquid crystal display panel 10)
Polarizing plate 11a (with protective laminate, thickness 230 μm)
Liquid crystal cell 1 (1200 μm thickness, transmittance of glass substrate 1.49)
Polarizing plate 11b (without protective laminate, thickness 166 μm)
Optical layer laminate 30: GD221 manufactured by GLOTEC (DPOP: Optical composite function sheet)
Thickness of optical layer laminate 30: 380 μm
First adhesive layer 40a: TN20AIR manufactured by DIC Corporation
The pitch of the plurality of bonding portions 40p is 800 μm, and the dot diameter of the bonding portions 40p is 300 μm.
Occupied area ratio of the plurality of bonding portions 40p in the first bonding layer 40a: 50%
Refractive index of first adhesive layer 40a: about 1.49 Thickness of first adhesive layer 40a: 25 μm
Phosphor layer 25 and protective layers 26a and 26b: quantum dot film manufactured by Hitachi Chemical Co., Ltd. Sum of thicknesses of phosphor layer 25 and protective layers 26a and 26b: 360 μm
Adhesive layer 40b (25 μm thickness)
Wavelength-selective reflective layer 28: Picasus sheet manufactured by Toray Industries, Inc. Thickness of wavelength-selective reflective layer 28: 70 μm
Protective layer (thickness 60μm)
　・実施例２（下記以外は実施例１と同じ）
　　光学層積層体３０Ｂ：（液晶表示パネル１０側から順に）
　　　拡散接着層（ＰＳＡ（感圧接着剤））（厚さ５０μｍ）
　　　ＤＢＥＦ－ＱＶ２（ｃｏｒｅ）（厚さ９２μｍ）
　　　ＰＥＴフィルム：厚さ５０μｍ、屈折率１．５８
　　　プリズムシート３４ａのプリズム層３４ｐａ：＋４５°６０Ｐ、アクリル樹脂、厚さ３５μｍ、屈折率１．５６
　　　プリズムシート３４ａのベースフィルム３４ｂａ：ＰＥＴフィルム、厚さ５０μｍ、屈折率１．５８
　　　プリズムシート３４ｂのプリズム層３４ｐｂ：－４５°６０Ｐ、アクリル樹脂、厚さ３５μｍ、屈折率１．５６
　　　プリズムシート３４ｂのベースフィルム３４ｂｂ：ＰＥＴフィルム、厚さ５０μｍ、屈折率１．５８
　　　光拡散層３６の光拡散材（ビーズ）３６ｄ：厚さ３０μｍ、屈折率１．４３～１．６６程度
　　　光拡散層３６のベースフィルム３６ｂ：ＰＥＴフィルム、厚さ５０μｍ、屈折率：１．５８
　　　Ｍａｔｔｅ　Ｃｏａｔｉｎｇ：Ｈａｚｅ７５％、厚さ１０μｍ
　　　保護層：厚さ４０μｍ -Example 2 (except for the following, which is the same as Example 1)
Optical layer laminate 30B: (in order from the liquid crystal display panel 10 side)
Diffusion adhesive layer (PSA (pressure-sensitive adhesive)) (50 μm thickness)
DBEF-QV2 (core) (92 μm thick)
PET film: thickness 50 μm, refractive index 1.58
Prism layer 34pa of prism sheet 34a: + 45 ° 60P, acrylic resin, thickness 35 μm, refractive index 1.56
Base film 34ba of prism sheet 34a: PET film, thickness 50 μm, refractive index 1.58
Prism layer 34pb of prism sheet 34b: −45 ° 60P, acrylic resin, thickness 35 μm, refractive index 1.56
Base film 34bb of prism sheet 34b: PET film, thickness 50 μm, refractive index 1.58
Light diffusing material (beads) 36d of the light diffusing layer 36: thickness 30 μm, refractive index of about 1.43 to 1.66 Base film 36b of the light diffusing layer 36: PET film, thickness 50 μm, refractive index: 1.58
Matte Coating: Haze 75%, thickness 10 μm
Protective layer: thickness 40 μm
　・実施例３（下記以外は実施例２と同じ）
　　第１接着層４０ａ：DIC株式会社製のTN06AIR 
　　　複数の接着部４０ｐのピッチ580μm、接着部４０ｐのドット径220μm
　　　第１接着層４０ａにおける複数の接着部４０ｐの占有面積率：５０％ Example 3 (except for the following, which is the same as Example 2)
First adhesive layer 40a: TN06AIR manufactured by DIC Corporation
Pitch 580 μm of plural bonding parts 40p, dot diameter 220 μm of bonding parts 40p
Occupied area ratio of the plurality of bonding portions 40p in the first bonding layer 40a: 50%
　表１および図７に実施例１～４および比較例の評価結果を示す。 Table 1 and FIG. 7 show the evaluation results of Examples 1 to 4 and Comparative Example.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　比較例においては、液晶表示パネル９９０とバックライト装置９５０Ｂとの間に、３ｍｍ程度の空隙Ｇが設けられている。これに対して、実施例１～４においては、いずれも、液晶表示パネルとバックライト装置（光学層積層体）とは接着層によって貼り合わされているので、液晶表示パネルとバックライト装置との間に空隙を有しない。さらに、比較例のバックライト装置９５０Ｂは、拡散板９４０（厚さＤｄ：２ｍｍ）を有するのに対し、実施例１～４は、いずれもＬＥＤ基板と波長選択反射層との間に拡散板を有しない。従って、実施例１～４は、比較例よりも少なくとも５ｍｍ程度薄くすることができた。 In the comparative example, a gap G of about 3 mm is provided between the liquid crystal display panel 990 and the backlight device 950B. On the other hand, in each of Examples 1 to 4, since the liquid crystal display panel and the backlight device (optical layer laminate) are bonded to each other by the adhesive layer, the liquid crystal display panel and the backlight device are not bonded to each other. Has no voids. Further, the backlight device 950B of the comparative example has a diffusion plate 940 (thickness Dd: 2 mm), whereas the backlight devices 950B of Examples 1 to 4 each include a diffusion plate between the LED substrate and the wavelength selective reflection layer. Do not have. Therefore, Examples 1 to 4 could be made at least about 5 mm thinner than the Comparative Example.
　さらに、表１および図７に示すように、空気層を形成する第１接着層４０ａを有する実施例１～３は、いずれも、空気層を形成しない第１接着層４０Ｒを有する実施例４よりも高い輝度を呈した。 Further, as shown in Table 1 and FIG. 7, Examples 1 to 3 having the first adhesive layer 40a forming the air layer are all different from Examples 4 having the first adhesive layer 40R not forming the air layer. Also exhibited high brightness.
　本発明の実施形態は、ＬＥＤバックライトを備える液晶表示装置として好適に用いられる。 The embodiment of the present invention is suitably used as a liquid crystal display device having an LED backlight.
１　　液晶セル
１０　液晶表示パネル
１０ｒ　背面
２１　　ＬＥＤ基板
２１ｓ　表面
２２　　ＬＥＤチップ
２５　　蛍光体層
２５ｑ　量子ドット蛍光体
２６ａ、２６ｂ　保護層
２８　　波長選択反射層
３０、３０Ｂ　　光学層積層体
３２　　偏光選択反射層
３４ａ、３４ｂ　プリズムシート
３４ｂａ、３４ｂｂ　ベースフィルム
３４ｐａ、３４ｐｂ　プリズム層
３６　　光拡散層
３６ｂ　ベースフィルム
３６ｄ　光拡散材
４０ａ　第１接着層
４０ｐ　接着部
４０ｂ、４０ｃ、４０ｄ、４０ｅ　接着層
５０　　バックライト装置
１００、１００Ｂ　液晶表示装置 Reference Signs List 1 liquid crystal cell 10 liquid crystal display panel 10r back surface 21 LED substrate 21s surface 22 LED chip 25 phosphor layer 25q quantum dot phosphor 26a, 26b protective layer 28 wavelength selective reflection layer 30, 30B optical layer laminate 32 polarization selective reflection layer 34a, 34b prism sheet 34ba, 34bb base film 34pa, 34pb prism layer 36 light diffusion layer 36b base film 36d light diffusion material 40a first adhesive layer 40p adhesive portions 40b, 40c, 40d, 40e adhesive layer 50 backlight device 100, 100B liquid crystal display apparatus

Claims (24)

  1. 　液晶表示パネルと、前記液晶表示パネルの背面に向けて光を出射するバックライト装置とを備える液晶表示装置であって、
    　前記バックライト装置は、
    　　前記液晶表示パネルの前記背面に向けて励起光を出射するように複数のＬＥＤチップが表面に配列されたＬＥＤ基板と、
    　　前記励起光を受けて、蛍光を発する蛍光体を含む蛍光体層と、
    　　前記蛍光体層と前記ＬＥＤ基板との間に配置され、前記励起光の透過率が前記蛍光の透過率よりも高い波長選択反射層と、
    　　前記蛍光体層の前記液晶表示パネル側に配置された光学層積層体と
    を有し、
    　前記光学層積層体、前記蛍光体層および前記波長選択反射層は、前記液晶表示パネルの前記背面に、第１接着層を含む複数の接着層を介して一体に固定されている、液晶表示装置。     A liquid crystal display device comprising: a liquid crystal display panel; and a backlight device that emits light toward a back surface of the liquid crystal display panel,
    The backlight device,
    An LED substrate on which a plurality of LED chips are arranged on the surface so as to emit excitation light toward the rear surface of the liquid crystal display panel,
    A phosphor layer containing a phosphor that emits fluorescence upon receiving the excitation light,
    A wavelength-selective reflection layer disposed between the phosphor layer and the LED substrate, wherein the transmittance of the excitation light is higher than the transmittance of the fluorescence;
    An optical layer laminate disposed on the liquid crystal display panel side of the phosphor layer,
    A liquid crystal display device, wherein the optical layer laminate, the phosphor layer, and the wavelength selective reflection layer are integrally fixed to the back surface of the liquid crystal display panel via a plurality of adhesive layers including a first adhesive layer. .
  2. 　前記第１接着層は、前記光学層積層体と前記蛍光体層との間に形成されており、前記第１接着層は、離散的に配置された複数の接着部を有し、かつ、前記光学層積層体と前記蛍光体層との間に空気層を形成している、請求項１に記載の液晶表示装置。 The first adhesive layer is formed between the optical layer laminate and the phosphor layer, the first adhesive layer has a plurality of discretely arranged adhesive portions, and The liquid crystal display device according to claim 1, wherein an air layer is formed between an optical layer laminate and the phosphor layer.
  3. 　前記第１接着層における前記複数の接着部の占有面積率は５０％以下である、請求項２に記載の液晶表示装置。 The liquid crystal display device according to claim 2, wherein the occupied area ratio of the plurality of bonding portions in the first bonding layer is 50% or less.
  4. 　前記光学層積層体は、光拡散層を有する、請求項１から３のいずれかに記載の液晶表示装置。 The liquid crystal display device according to any one of claims 1 to 3, wherein the optical layer laminate has a light diffusion layer.
  5. 　前記光拡散層は、前記光学層積層体に含まれる層のうち、前記蛍光体層の最も近くに形成されている、請求項４に記載の液晶表示装置。 The liquid crystal display device according to claim 4, wherein the light diffusion layer is formed closest to the phosphor layer among the layers included in the optical layer laminate.
  6. 　前記光学層積層体は、偏光選択反射層を有する、請求項１から５のいずれかに記載の液晶表示装置。 6. The liquid crystal display device according to claim 1, wherein the optical layer laminate has a polarization selective reflection layer.
  7. 　前記光拡散層は、前記偏光選択反射層よりも、前記ＬＥＤ基板の近くに配置されている、請求項４または５を引用する請求項６に記載の液晶表示装置。 7. The liquid crystal display device according to claim 6, wherein the light diffusion layer is disposed closer to the LED substrate than the polarization selective reflection layer. 8.
  8. 　前記光学層積層体は、少なくとも１枚のプリズムシートを有する、請求項１から７のいずれかに記載の液晶表示装置。 The liquid crystal display device according to any one of claims 1 to 7, wherein the optical layer laminate has at least one prism sheet.
  9. 　前記少なくとも１枚のプリズムシートは、それぞれのプリズムの稜線が互いに略直交する様に配置された２枚のプリズムシートを含む、請求項８に記載の液晶表示装置。 The liquid crystal display device according to claim 8, wherein the at least one prism sheet includes two prism sheets arranged such that ridges of the respective prisms are substantially orthogonal to each other.
  10. 　前記光学層積層体は、それぞれのプリズムの稜線が互いに略直交する様に配置された２枚のプリズムシートと、前記２枚のプリズムシートの上に配置された偏光選択反射層とを有し、前記２枚のプリズムシートのうち、前記蛍光体層に近い方のプリズムシートの、前記ＬＥＤ基板を向く表面は鏡面である、請求項１から５のいずれかに記載の液晶表示装置。 The optical layer laminate includes two prism sheets arranged such that the ridge lines of each prism are substantially orthogonal to each other, and a polarization selective reflection layer arranged on the two prism sheets, The liquid crystal display device according to claim 1, wherein, of the two prism sheets, a surface of the prism sheet closer to the phosphor layer facing the LED substrate is a mirror surface.
  11. 　前記光学層積層体の前記ＬＥＤ基板を向く表面は鏡面である、請求項１から１０のいずれかに記載の液晶表示装置。 The liquid crystal display device according to any one of claims 1 to 10, wherein a surface of the optical layer laminate facing the LED substrate is a mirror surface.
  12. 　前記ＬＥＤ基板と前記波長選択反射層との間に光拡散層を有しない、請求項１から１１のいずれかに記載の液晶表示装置。 12. The liquid crystal display device according to claim 1, wherein no light diffusion layer is provided between the LED substrate and the wavelength selective reflection layer.
  13. 　前記複数の接着層は、前記光学層積層体と前記蛍光体層との間に形成された２以上の接着層を有し、前記第１接着層は、前記２以上の接着層のうち、前記光学層積層体の最も近くに配置されている、請求項１から１２のいずれかに記載の液晶表示装置。 The plurality of adhesive layers have two or more adhesive layers formed between the optical layer laminate and the phosphor layer, and the first adhesive layer is one of the two or more adhesive layers. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is arranged closest to the optical layer laminate.
  14. 　前記ＬＥＤ基板の前記表面の、前記複数のＬＥＤチップの間の領域には、前記蛍光および前記励起光を反射する反射部材を有しない、請求項１から１３のいずれかに記載の液晶表示装置。 The liquid crystal display device according to any one of claims 1 to 13, wherein a reflection member that reflects the fluorescence and the excitation light is not provided in a region between the plurality of LED chips on the surface of the LED substrate.
  15. 　前記ＬＥＤ基板の前記表面の、前記複数のＬＥＤチップの間の領域には、前記蛍光を吸収する吸収部材が設けられている、請求項１から１４のいずれかに記載の液晶表示装置。 The liquid crystal display device according to any one of claims 1 to 14, wherein an absorption member for absorbing the fluorescence is provided in a region between the plurality of LED chips on the surface of the LED substrate.
  16. 　前記蛍光体は、量子ドット蛍光体を含む、請求項１から１５のいずれかに記載の液晶表示装置。 16. The liquid crystal display device according to claim 1, wherein the phosphor includes a quantum dot phosphor.
  17. 　請求項１から１６のいずれかに記載の液晶表示装置を製造する方法であって、
    　前記液晶表示パネルを用意する工程Ａと、
    　前記工程Ａの後に、前記液晶表示パネルの前記背面上に、前記光学層積層体、前記蛍光体層および前記波長選択反射層を前記複数の接着層を介して一体に固定する工程Ｂと、
    　前記複数のＬＥＤチップが前記表面に配列された前記ＬＥＤ基板を用意する工程Ｃと、
    　前記工程Ｂおよび前記工程Ｃの後に、前記液晶表示パネルの前記背面に前記複数のＬＥＤチップが向くように、前記液晶表示パネルと前記ＬＥＤ基板とを固定する工程Ｄと
    を包含する、製造方法。     A method for manufacturing a liquid crystal display device according to any one of claims 1 to 16,
    A step A of preparing the liquid crystal display panel;
    After the step A, a step B of integrally fixing the optical layer laminate, the phosphor layer, and the wavelength selective reflection layer on the back surface of the liquid crystal display panel via the plurality of adhesive layers;
    A step C of preparing the LED substrate on which the plurality of LED chips are arranged on the surface;
    A manufacturing method comprising, after the steps B and C, fixing the liquid crystal display panel and the LED substrate so that the plurality of LED chips face the rear surface of the liquid crystal display panel.
  18. 　前記工程Ｂは、
    　　前記蛍光体層と前記波長選択反射層とを一体に固定する工程Ｂ１と、
    　　前記液晶表示パネルの前記背面上に、前記光学層積層体を固定する工程Ｂ２と、
    　　前記工程Ｂ１および工程Ｂ２の後に、前記光学層積層体と前記蛍光体層とを貼り合せる工程Ｂ３と
    を包含する、請求項１７に記載の製造方法。     The step B includes:
    A step B1 of integrally fixing the phosphor layer and the wavelength selective reflection layer,
    Fixing the optical layer laminate on the back surface of the liquid crystal display panel; and B2.
    The method according to claim 17, further comprising a step (B3) of bonding the optical layer laminate and the phosphor layer after the steps (B1) and (B2).
  19. 　前記工程Ｂは、前記光学層積層体、前記蛍光体層および前記波長選択反射層を一体に固定した後、前記液晶表示パネルの前記背面に固定する工程を包含する、請求項１７に記載の製造方法。 18. The manufacturing method according to claim 17, wherein the step B includes a step of fixing the optical layer laminate, the phosphor layer and the wavelength selective reflection layer integrally, and then fixing the optical layer laminate, the phosphor layer and the wavelength selective reflection layer to the rear surface of the liquid crystal display panel. Method.
  20. 　前記工程Ｂは、前記蛍光体層と前記波長選択反射層とを一体に固定した後、前記光学層積層体と一体化する工程を包含する、請求項１９に記載の製造方法。 20. The manufacturing method according to claim 19, wherein the step B includes a step of integrally fixing the phosphor layer and the wavelength selective reflection layer and then integrating the phosphor layer and the wavelength selective reflection layer with the optical layer laminate.
  21. 　前記工程Ｂは、前記光学層積層体と前記蛍光体層とを一体に固定した後、前記波長選択反射層と一体化する工程を包含する、請求項１９に記載の製造方法。 20. The method according to claim 19, wherein the step B includes a step of integrally fixing the optical layer laminate and the phosphor layer and then integrating the optical layer laminate and the phosphor layer with the wavelength selective reflection layer.
  22. 　前記光学層積層体と前記蛍光体層とを互いに接着する工程は、ベースフィルムと前記ベースフィルムの両側に形成された２つの接着層とを有する両面接着フィルムを用いて行われ、前記２つの接着層のうちの前記光学層積層体に近い方の接着層は、離散的に配置された複数の接着部を有する、請求項１７から２１のいずれかに記載の製造方法。 The step of bonding the optical layer laminate and the phosphor layer to each other is performed using a double-sided adhesive film having a base film and two adhesive layers formed on both sides of the base film. The manufacturing method according to any one of claims 17 to 21, wherein the adhesive layer closer to the optical layer laminate among the layers has a plurality of discretely arranged adhesive portions.
  23. 　前記光学層積層体と前記蛍光体層とを互いに接着する工程は、離散的に配置された複数の接着部を有する接着層の両側に、前記光学層積層体および前記蛍光体層を接触させる工程を包含する、請求項１７から２１のいずれかに記載の製造方法。 The step of adhering the optical layer laminate and the phosphor layer to each other includes contacting the optical layer laminate and the phosphor layer on both sides of an adhesive layer having a plurality of discretely arranged adhesive portions. The method according to any one of claims 17 to 21, comprising:
  24. 　前記光学層積層体と前記蛍光体層とを互いに接着する工程は、前記光学層積層体の一面に接着層を付与した後、前記蛍光体層と一体化する工程を包含する、または、前記蛍光体層の一面に接着層を付与した後、前記光学層積層体と一体化する工程を包含する、請求項１７から２３のいずれかに記載の製造方法。 The step of adhering the optical layer laminate and the phosphor layer to each other includes a step of applying an adhesive layer to one surface of the optical layer laminate and then integrating the phosphor layer with the phosphor layer, or The method according to any one of claims 17 to 23, comprising a step of providing an adhesive layer on one surface of the body layer and then integrating the adhesive layer with the optical layer laminate.
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